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1
Liu, Guoping, Lianbo Zeng, Xiaojun Wang, Mehdi Ostadhassan, Zhenlin Wang, Zhe Mao y Qi Tie. "Natural fractures in deep tight gas sandstone reservoirs in the thrust belt of the southern Junggar Basin, northwestern China". Interpretation 8, n.º 4 (23 de julio de 2020): SP81—SP93. http://dx.doi.org/10.1190/int-2020-0051.1.
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The development of natural fractures is a significant characteristic of the Jurassic deep tight sandstone reservoirs in the thrust belt of the southern Junggar Basin, and these reservoirs have a great potential for natural gas resources. Based on the analyses of outcrops, cores, thin sections, and other laboratory data, natural fractures in these reservoirs are mainly tectonic ones, which appear in groups and vary in scale, dip angle, and density. We have classified fractures in thin sections into intragranular, grain boundary, and transgranular ones depending on their relationship with minerals grains. Almost 58% of the whole fracture population is opening-mode fractures, and calcite is the main filling mineral for the remaining ones. Fracture apertures vary based on their types, where transgranular fractures are the widest, followed by grain boundary and intragranular ones. Lithology, rock mechanical mechanics layers, and structures control the development of natural fractures. Fractures are more frequent in siltstone and fine sandstone. Sandstones with larger mineral grains are more likely to develop grain boundary and intragranular fractures. Intralayer fractures are the dominant ones, which intersect the rock mechanics interface at high angles or perpendicularly. The linear density of these fractures decreases when the thickness of the rock-mechanics layer increases. Furthermore, fractures have a higher degree of development in the hanging wall of the faults, with the degree decreasing when the distance from the fault plane increases. Additionally, the development degree of fractures in the damage zone is better than the adjacent rocks, and the width of damage zones is a function of the amount of fault displacement.
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Gong, Lei, Shuai Gao, Shu Ju Guo, Jian Guo Huang y Xian Xian Tao. "Characteristics and Sequences of Fractures in the Tight Conglomerate Reservoirs of Jiulongshan Structure". Advanced Materials Research 900 (febrero de 2014): 689–92. http://dx.doi.org/10.4028/www.scientific.net/amr.900.689.
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Fracture is an important controlling factor for the distribution of natural gas reservoirs in the tight conglomerate reservoirs in the Lower Jurassic Zhenzhuchong Formation at the north of Western Sichuan basin. Using the data of outcrops, cores, image logs and thin sections, combined with experimental analysis, we analyze the fracture origin types, distribution characteristics and formation sequences. There are three types of fractures, i.e. tectonic fractures, diagenetic fractures and original fractures in the tight conglomerate reservoirs. Among them, tectonic fractures are dominant, which can be classified into four sets, i.e. E-W, nearly S-W, NWW-SEE, NEE-SWW orientations. According to the statistics of areal density and fractal dimension, the average fracture areal density is 0.31cm/cm2, with the bulk in the range of 0.15-0.60cm/cm2. The fracture fractal dimensions are distributed at 0.95-1.70. There is a well positive correlation between fracture areal density and fractal dimension. Micro-fractures are important channels that connect matrix intergranular pores and intragranular dissolved pores, which improve the connectivity among pores. The tectonic fractures in the study area were formed in two periods, i.e. the end of Cretaceous and the end of Neogene.
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Nian, Tao, Yanze Li, Tao Hou, Chengqian Tan y Chao Liu. "Natural fractures at depth in the Lower Cretaceous Kuqa Depression tight sandstones: identification and characteristics". Geological Magazine 157, n.º 8 (13 de enero de 2020): 1299–315. http://dx.doi.org/10.1017/s0016756819001444.
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AbstractThe Kuqa Depression in the northern Tarim Basin, NW China, is characterized by fault-controlled anticlines where natural fractures may influence production. Natural fractures in the Lower Cretaceous tight sandstones in the depression have been studied using seismic profiles, borehole images, cores and thin-sections. Results show that thrust faults, two types of opening-mode macrofractures and two types of microfractures are present. Thrust faults were generated during Cenozoic N–S-directed tectonic shortening and have hydraulically linked Jurassic source rocks and Cretaceous sandstones. Opening-mode fractures can be subdivided on the basis of sizes, filling characteristics and distribution patterns. Type 1 macrofractures are barren or mainly calcite-lined. They have straight traces with widths (opening displacements) that are of the order of magnitude of 10 μm, suggesting that their primary role is that of migration channels. Type 2 macrofractures are calcite-filled opening-mode fractures. They have an elliptical or tabular shape with sharply tapering tips. Transgranular microfractures are lens-shaped and open or filled mostly by calcite; maximum widths range between 0.01 mm and 0.1 mm. Intragranular microfractures are the most common microfracture type. They are filled by calcite, feldspar or quartz. The macrofractures and transgranular microfractures have regular distributions, while most intragranular microfractures are irregularly distributed owing to their inherited origin. The results imply that natural fractures in the tight sandstones were formed as tectonic, diagenetic and natural hydraulic origins. In situ stress and cementation analyses suggest that Type 1 macrofractures and their genesis-related microfractures have controlled the present flow system of the tight sandstones.
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Campbell, Oliver, Tom Blenkinsop, Oscar Gilbert y Lisa Mol. "Surface and Subsurface Damage Caused by Bullet Impacts into Sandstone". Geosciences 11, n.º 9 (17 de septiembre de 2021): 395. http://dx.doi.org/10.3390/geosciences11090395.
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The shift of armed conflicts to more urbanised environments has increased the risk to cultural heritage sites. Small arms impacts are ubiquitous in these circumstances, yet the effects and mechanisms of damage caused are not well known. A sandstone target was shot under controlled conditions to investigate surface and subsurface damage. A 3D model of the damaged block, created by structure from motion photogrammetry, shows that internal fracturing was at least as extensive as the visible surface fractures. Backscatter electron imaging of the damaged surface shows a shift from intragranular fracturing and grain size reduction at <5 mm from the impact point to primarily circumgranular fracturing and grain ‘plucking’ at 20 mm from the impact point. Internal fracture intensity decreased with distance from the centre of the crater. Volumes around the impact point are therefore at greater risk of subsequent weathering deterioration, but significant damage extends to the periphery of the target, rendering whole blocks vulnerable. The surface crater, despite being one of the most conspicuous aspects of conflict damage, has many times less area than internal and surface fractures.
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Desbois, Guillaume, Nadine Höhne, Janos L. Urai, Pierre Bésuelle y Gioacchino Viggiani. "Deformation in cemented mudrock (Callovo–Oxfordian Clay) by microcracking, granular flow and phyllosilicate plasticity: insights from triaxial deformation, broad ion beam polishing and scanning electron microscopy". Solid Earth 8, n.º 2 (9 de marzo de 2017): 291–305. http://dx.doi.org/10.5194/se-8-291-2017.
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Abstract. The macroscopic description of deformation and fluid flow in mudrocks can be improved by a better understanding of microphysical deformation mechanisms. Here we use a combination of scanning electron microscopy (SEM) and broad ion beam (BIB) polishing to study the evolution of microstructure in samples of triaxially deformed Callovo–Oxfordian Clay. Digital image correlation (DIC) was used to measure strain field in the samples and as a guide to select regions of interest in the sample for BIB–SEM analysis. Microstructures show evidence for dominantly cataclastic and minor crystal plastic mechanisms (intergranular, transgranular, intragranular cracking, grain rotation, clay particle bending) down to the nanometre scale. At low strain, the dilatant fabric contains individually recognisable open fractures, while at high strain the reworked clay gouge also contains broken non-clay grains and smaller pores than the undeformed material, resealing the initial fracture porosity.
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Wang, Jingyi, Qinhong Hu, Mengdi Sun, Zhongxian Cai, Cong Zhang y Tao Zhang. "Micro- and Nanoscale Pore Structure Characterization of Carbonates from the Xiaoerbulake Formation in the Tarim Basin, Northwest China". Geofluids 2021 (27 de abril de 2021): 1–20. http://dx.doi.org/10.1155/2021/6667496.
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The evaluation of pore structure is an essential part in the assessment of carbonate reservoirs. The structures (geometry and connectivity) of nm to μm-scale pore networks in outcrop samples of carbonates from Xiaoerbulake Formation in Tarim Basin of China were studied by using optical microscopy, field emission-scanning electron microscopy (FE-SEM), as well as mercury intrusion porosimetry (MIP) with fractal analyses of the data, and spontaneous imbibition tests (distilled water). The results demonstrate that the lithologies are micritic dolomites, fine-to-medium-to-coarse crystalline dolomites, microbial dolomites, and dolarenite. At micro- to nanoscales in size, pore types are dominated by intergranular, intercrystalline, and intragranular (e.g., dissolution) pores. These pore networks have pore-throat diameters from 0.01 to >10 μm. Compared with a nanoscale pore network, the μm-scale pore networks are relatively well connected and serve as the most important permeability pathways. Although the pore volume accounts for most of the total porosity, the permeability of nanoscale pore networks is low. The existence of micro-nano-fractures could improve connectivity, especially for the nanoscale pore networks, by linking the intragranular (dissolution) pores which are mostly in the range of nm-scale.
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DJAMAL, BOUTASSOUNA, RENÉ LE GALL y IBEN KHALDOUN LEFKAIER. "EFFECT OF SMALL BULK SULFUR CONTENT AND ANNEALING TEMPERATURE ON THE INTERGRANULAR FRACTURING SUSCEPTIBILITY OF METALLIC NICKEL". Surface Review and Letters 23, n.º 06 (17 de noviembre de 2016): 1650050. http://dx.doi.org/10.1142/s0218625x16500505.
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In this paper, we investigate the influence of temperature on the nickel grain boundary equilibrium segregation of sulfur and the resulting intergranular fracturing susceptibility. Auger electron spectroscopy has been used to study equilibrium segregation of sulfur to the grain boundaries of a metallic nickel, with a mass bulk content of 3.6[Formula: see text]ppm in sulfur. Samples were first annealed at adequate temperatures for sufficiently large equilibrium time, and then quenched in water at room temperature. The analysis carried out shows a significant increase of sulfur concentration in the grain boundary with decreasing temperature. However, the sulfur content in the grain boundary shows a drastic shrink at 700[Formula: see text]C. This can be interpreted by the formation of an aggregate sulfide compound in the area of the grain boundaries. At 650[Formula: see text]C, in situ brittle fracture becomes unworkable and only intragranular fractures are observed. Using the results obtained through the investigation of the grain boundaries by Auger spectroscopy, the standard segregation energy is estimated as [Formula: see text].
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Crompton, Jeff W., Gwenn E. Flowers y Brendan Dyck. "Characterization of glacial silt and clay using automated mineralogy". Annals of Glaciology 60, n.º 80 (diciembre de 2019): 49–65. http://dx.doi.org/10.1017/aog.2019.45.
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AbstractGlacial erosion produces vast quantities of fine-grained sediment that has a far-reaching impact on Earth surface processes. To gain a better understanding of the production of glacial silt and clay, we use automated mineralogy to quantify the microstructure and mineralogy of rock and sediment samples from 20 basins in the St. Elias Mountains, Yukon, Canada. Sediments were collected from proglacial streams, while rock samples were collected from ice marginal outcrops and fragmented using electrical pulse disaggregation. For both rock fragments and sediments, we observe a log-normal distribution of grain sizes and a sub-micrometer terminal grain size. We find that the abrasion of silt and clay results in both rounding and the exploitation of through-going fractures. The abundance of inter- versus intragranular fractures depends on mineralogy and size. Unlike the relatively larger grains, where crushing and abrasion are thought to exploit and produce discrete populations of grain sizes, the comminution of fines leads to a grain size, composition and rounding that is continuously distributed across size, and highly dependent on source-rock properties.
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Hentschel, Felix, Claudia A. Trepmann y Emilie Janots. "Deformation of feldspar at greenschist facies conditions – the record of mylonitic pegmatites from the Pfunderer Mountains, Eastern Alps". Solid Earth 10, n.º 1 (17 de enero de 2019): 95–116. http://dx.doi.org/10.5194/se-10-95-2019.
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Abstract. Deformation microstructures of albitic plagioclase and K-feldspar were investigated in mylonitic pegmatites from the Austroalpine basement south of the western Tauern Window by polarized light microscopy, electron microscopy and electron backscatter diffraction to evaluate feldspar deformation mechanisms at greenschist facies conditions. The main mylonitic characteristics are alternating almost monophase quartz and albite layers, surrounding porphyroclasts of deformed feldspar and tourmaline. The dominant deformation microstructures of K-feldspar porphyroclasts are intragranular fractures at a high angle to the stretching lineation. The fractures are healed or sealed by polyphase aggregates of albite, K-feldspar, quartz and mica, which also occur along intragranular fractures of tourmaline and strain shadows around other porphyroclasts. These polyphase aggregates indicate dissolution–precipitation creep. K-feldspar porphyroclasts are partly replaced by albite characterized by a cuspate interface. This replacement is interpreted to take place by interface-coupled dissolution–precipitation driven by a solubility difference between K-feldspar and albite. Albite porphyroclasts are replaced at boundaries parallel to the foliation by fine-grained monophase albite aggregates of small strain-free new grains mixed with deformed fragments. Dislocation glide is indicated by bent and twinned albite porphyroclasts with internal misorientation. An indication of effective dislocation climb with dynamic recovery, for example, by the presence of subgrains, is systematically missing. We interpret the grain size reduction of albite to be the result of coupled dislocation glide and fracturing (low-temperature plasticity). Subsequent growth is by a combination of strain-induced grain boundary migration and formation of growth rims, resulting in an aspect ratio of albite with the long axis within the foliation. This strain-induced replacement by nucleation (associated dislocation glide and microfracturing) and subsequent growth is suggested to result in the observed monophase albite layers, probably together with granular flow. The associated quartz layers show characteristics of dislocation creep by the presence of subgrains, undulatory extinction and sutured grain boundaries. We identified two endmember matrix microstructures: (i) alternating layers of a few hundred micrometres' width, with isometric, fine-grained feldspar (on average 15 µm in diameter) and coarse-grained quartz (a few hundred micrometres in diameter), representing lower strain compared to (ii) alternating thin layers of some tens of micrometres' width composed of fine-grained quartz (<20 µm in diameter) and coarse elongated albite grains (long axis of a few tens of micrometres) defining the foliation, respectively. Our observations indicate that grain size reduction by strain-induced replacement of albite (associated dislocation glide and microfracturing) followed by growth and granular flow simultaneous with dislocation creep of quartz are playing the dominating role in formation of the mylonitic microstructure.
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Zhong, Liqiong, Hao Hu, Yilong Liang y Chaowen Huang. "High Cycle Fatigue Performance of Inconel 718 Alloys with Different Strengths at Room Temperature". Metals 9, n.º 1 (21 de diciembre de 2018): 13. http://dx.doi.org/10.3390/met9010013.
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In this paper, the high cycle fatigue performance of solid solution state and aged Inconel 718 superalloys was studied at room temperature. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the original structural features and fatigue deformation features of two kinds of alloys. SEM, laser scanning confocal microscopy, and electron backscatter diffraction (EBSD) were used to analyze the secondary fracture features of the fatigue fracture morphology and fatigue fracture profile. The results showed that the aging treatment significantly affected the strength and plasticity of the alloy, which in turn affected the fatigue performance of the alloy. After the aging treatment, the yield strength σs and the tensile strength σb of the Inconel 718 alloy increased by 152% and 65.9%, respectively, compared with those of the solid solution state, but the rate of elongation δ and rate of contraction in the cross-section area φ decreased by 63.7% and 52.3%, respectively. The fatigue limit of the aged state was lower than that of the solid solution state by 6.3%. The quadratic function relationship between the high cycle fatigue limit σ−1 and the tensile strength σb of the Inconel 718 superalloy at room temperature was σ−1 = σb · (0.869−3.67 × 10−4 · σb). An analysis of the fatigue fracture mechanism showed that the fatigue fractures before and after aging were all initiated in the grains oriented relatively unfavorably on the surface of the sample, with a mixture of intergranular and transgranular propagation after the transgranular propagation of several grains. The higher plasticity of the solid solution state Inconel 718 alloy resulted in a large number of slip deformation zones under high cycle fatigue loads, and the plastic deformation was relatively uniform. The lengths of the secondary fractures were as high as 120 μm, which formed the single-source plastic fatigue fracture that promoted an increase in the fatigue limit. After aging treatment, the higher strength of the Inconel 718 alloy made dislocation slip difficult under high cycle fatigue loads, and the plasticity compatible deformation capability was poor. When local dislocations slipped to the intragranular γ” phase, γ’ phase, or interfaces with nonmetallic compounds (NMCs), plugging occurred. The degree of stress concentration increased, causing the initiation of fatigue fracture; the secondary fracture was approximately 20 μm. Brittle cleavage due to multiple sources significantly reduced the fatigue limit.
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Wang, Jinkai, Zhang Jinliang y Jun Xie. "Analysis of the Factors that Influence Diagenesis in the Terminal Fan Reservoir of Fuyu Oil Layer in the Southern Songliao Basin, Northeast China". Open Geosciences 10, n.º 1 (31 de diciembre de 2018): 866–81. http://dx.doi.org/10.1515/geo-2018-0068.
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AbstractThe diagenesis mechanism and the physical properties of a terminal fan reservoir are determined by nuclear magnetic resonance (NMR), X-ray diffraction and scanning electron microscopy. The main provenance directions are NE and SE, and the two oppositely directed fans converge to form a small catchment basin. The mudstone color is red or purplish red, which accounts for 60% of the total rock. The sandstones are lithic-feldspar sandstones and feldspar-lithic sandstones, with a smaller quartz component relative to the adjacent sandstone formations. The reservoir mainly consists of intergranular pores (51%), intragranular pores (22%), corrosion pores (20%), micro-fractures (5%) and clay matrix pores (2%). The porosity of the reservoir is only 13%, and the throats are fine with high displacement pressure. The diagenetic processes included compaction, cementation, replacement, and dissolution, and the most influential factor on the reservoir porosity was compaction. The detrital rock cement mainly consists of clay minerals (48%), quartz (23%), carbonate (19%), feldspar (7%) and dawsonite (3%). Among them, the mixed I/S layer has the most content and the most important cementation. In addition, a small amount of dawsonite is found in the pores of the sandstone, which is a unique mineral that is related to the background of inorganic CO2. The main diagenesis factors that affected this sandstone’s porosity were compaction, early quartz overgrowth and calcite cementation, which reduced the porosity from 40% to approximately 8%. Although dissolution and fracture increased the porosity (from 8% to 26%), clay- and carbonate-mineral cementation during the late diagenesis period had a dramatic effect, forming a typical low-porosity and low-permeability reservoir.
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Jiao, Pengfei, Genshun Yao, Shangwen Zhou, Zhe Yu y Shiluo Wang. "A Comparative Study of the Micropore Structure between the Transitional and Marine Shales in China". Geofluids 2021 (7 de abril de 2021): 1–14. http://dx.doi.org/10.1155/2021/5562532.
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To compare the micropore structure of marine-continental transitional shale with marine shale, organic geochemical, field emission scanning electron microscopy, and low-temperature nitrogen adsorption experiments were conducted on shale samples from the Shanxi Formation in the eastern Ordos Basin and the Longmaxi Formation in the southern Sichuan Basin. The results show that Shanxi Formation shale has a smaller specific surface area and pore volume than Longmaxi Formation shale; therefore, the transitional shales fail to provide sufficient pore spaces for the effective storage and preservation of natural gas. Both the transitional and marine shales are in an overmature stage with high total organic carbon content, but they differ considerably in pore types and development degrees. Inorganic pores and fractures are dominantly developed in transitional shales, such as intragranular pores and clay mineral interlayer fractures, while organic nanopores are rarely developed. In contrast, organic pores are the dominant pore type in the marine shales and inorganic pores are rarely observed. The fractal analysis also shows that pore structure complexity and heterogeneity are quite different. These differences were related to different organic types, i.e., type I of marine shale and type III of transitional shale. Marine Longmaxi shale has experienced liquid hydrocarbon cracking, gas generation, and pore-forming processes, providing good conditions for natural gas to be preserved. However, during the evolution of transitional Shanxi shale, gas cannot be effectively preserved due to the lack of the above evolution processes, leading to the poor gas-bearing property. The detailed comparison of the micropore structure between the transitional and marine shales is of great importance for the future exploitation of marine-continental transitional shale gas in China.
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Xu, Zhaohui, Peiqiang Zhao, Zhenlin Wang, Mehdi Ostadhassan y Zhonghua Pan. "Characterization and Consecutive Prediction of Pore Structures in Tight Oil Reservoirs". Energies 11, n.º 10 (11 de octubre de 2018): 2705. http://dx.doi.org/10.3390/en11102705.
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The Lucaogou Formation in Jimuaser Sag of Junggar Basin, China is a typical tight oil reservoir with upper and lower sweet spots. However, the pore structure of this formation has not been studied thoroughly due to limited core analysis data. In this paper, the pore structures of the Lucaogou Formation were characterized, and a new method applicable to oil-wet rocks was verified and used to consecutively predict pore structures by nuclear magnetic resonance (NMR) logs. To do so, a set of experiments including X-ray diffraction (XRD), mercury intrusion capillary pressure (MICP), scanning electron microscopy (SEM) and NMR measurements were conducted. First, SEM images showed that pore types are mainly intragranular dissolution, intergranular dissolution, micro fractures and clay pores. Then, capillary pressure curves were divided into three types (I, II and III). The pores associated with type I and III are mainly dissolution and clay pores, respectively. Next, the new method was verified by “as received” and water-saturated condition T2 distributions of two samples. Finally, consecutive prediction in fourteen wells demonstrated that the pores of this formation are dominated by nano-scale pores and the pore structure of the lower sweet spot reservoir is more complicated than that in upper sweet spot reservoir.
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Winhausen, Lisa, Jop Klaver, Joyce Schmatz, Guillaume Desbois, Janos L. Urai, Florian Amann y Christophe Nussbaum. "Micromechanisms leading to shear failure of Opalinus Clay in a triaxial test: a high-resolution BIB–SEM study". Solid Earth 12, n.º 9 (23 de septiembre de 2021): 2109–26. http://dx.doi.org/10.5194/se-12-2109-2021.
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Abstract. A microphysics-based understanding of mechanical and hydraulic processes in clay shales is required for developing advanced constitutive models, which can be extrapolated to long-term deformation. Although many geomechanical tests have been performed to characterise the bulk mechanical, hydro-mechanical, and failure behaviour of Opalinus Clay, important questions remain about micromechanisms: how do microstructural evolution and deformation mechanisms control the complex rheology? What is the in situ microstructural shear evolution, and can it be mimicked in the laboratory? In this contribution, scanning electron microscopy (SEM) was used to image microstructures in an Opalinus Clay sample deformed in an unconsolidated–undrained triaxial compression test at 4 MPa confining stress followed by argon broad ion beam (BIB) polishing. Axial load was applied (sub-)perpendicular to bedding until the sample failed. The test was terminated at an axial strain of 1.35 %. Volumetric strain measurements showed bulk compaction throughout the compression test. Observations on the centimetre to micrometre scale showed that the samples exhibited shear failure and that deformation localised by forming a network of micrometre-wide fractures, which are oriented with angles of 50∘ with respect to horizontal. In BIB–SEM at the grain scale, macroscale fractures are shown to be incipient shear bands, which show dilatant intergranular and intragranular microfracturing, granular flow, bending of phyllosilicate grains, and pore collapse in fossils. Outside these zones, no deformation microstructures were observed, indicating only localised permanent deformation. Thus, micromechanisms of deformation appear to be controlled by both brittle and ductile processes along preferred deformation bands. Anastomosing networks of fractures develop into the main deformation bands with widths up to tens of micrometres along which the sample fails. Microstructural observations and the stress–strain behaviour were integrated into a deformation model with three different stages of damage accumulation representative for the deformation of the compressed Opalinus Clay sample. Results on the microscale explain how the sample locally dilates, while bulk measurement shows compaction, with an inferred major effect on permeability by an increase in hydraulic conductivity within the deformation band. Comparison with the microstructure of highly strained Opalinus Clay in fault zones shows partial similarity and suggests that during long-term deformation additional solution–precipitation processes operate.
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Wang, Yuwei, Mingyue He, Wei Yan, Mei Yang y Xi Liu. "Jianite: Massive Dunite Solely Made of Virtually Pure Forsterite from Ji’an County, Jilin Province, Northeast China". Minerals 10, n.º 3 (29 de febrero de 2020): 220. http://dx.doi.org/10.3390/min10030220.
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A rare massive yellowish-green serpentinized dunite, covering a minimum area up to ~50 m2, has been found in Ji’an County, Jilin Province, Northeast China. It contains primary olivine and secondary serpentine (antigorite) and brucite. Other primary minerals like orthopyroxene, clinopyroxene, and aluminum-rich phase (such as garnet, spinel, and plagioclase), frequently appearing in ultramafic rocks, have not been identified. The olivine is essentially pure forsterite, with an Mg# (100 × Mg/(Mg + Fe)) of ~99.6–99.7. Due to these distinct features, we especially name the protolith of this dunite as jianite (集安岩). The forsterite grains range up to ~2 mm, show clear equilibrium textures such as nearly straight grain boundaries and ~120° dihedral angles at their triple junctions, and display no intragranular or intergranular composition variations. They are extensively ruptured and hydrated (i.e., serpentinized), with the fractures (and the grain boundaries as well) filled by fine-grained antigorite (ideally Mg6(Si4O10)(OH)8) and brucite (ideally Mg(OH)2). These secondary phases are also extremely poor in Fe, indicating a good chemical equilibrium with the forsterite. The serpentinization reaction may have proceeded as forsterite + fluid = antigorite + brucite at temperatures of ~425(25) °C and at relatively low but undetermined pressures. The fluid was likely a B-rich, but Si-poor dilute aqueous fluid, as implied by the trace element characteristics and water-related infrared features of the forsterites in equilibrium. The petrogenesis of the jianite is presently unclear.
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Fan, Zhuoying, Jiagen Hou, Chengyan Lin y Xinmin Ge. "A new workflow to improve the carbonate reservoir types discrimination combing the empirical model decomposition and energy entropy classification methods". Interpretation 6, n.º 3 (1 de agosto de 2018): T555—T567. http://dx.doi.org/10.1190/int-2017-0080.1.
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Classification and well-logging evaluation of carbonate reservoir rock is very difficult. On one side, there are many reservoir pore spaces developed in carbonate reservoirs, including large karst caves, dissolved pores, fractures, intergranular dissolved pores, intragranular dissolved pores, and micropores. On the other side, conventional well-logging response characteristics of the various pore systems can be similar, making it difficult to identify the type of pore systems. We have developed a new reservoir rock-type characterization workflow. First, outcrop observations, cores, well logs, and multiscale data were used to clarify the carbonate reservoir types in the Ordovician carbonates of the Tahe Oilfield. Three reservoir rock types were divided based on outcrop, core observation, and thin section analysis. Microscopic and macroscopic characteristics of various rock types and their corresponding well-log responses were evaluated. Second, conventional well-log data were decomposed into multiple band sets of intrinsic mode functions using empirical mode decomposition method. The energy entropy of each log curve was then investigated. Based on the decomposition results, the characteristics of each reservoir type were summarized. Finally, by using the Fisher discriminant, the rock types of the carbonate reservoirs could be identified reliably. Comparing with conventional rock type identification methods based on conventional well-log responses only, the new workflow proposed in this paper can effectively cluster data within each rock types and increase the accuracy of reservoir type-based hydrocarbon production prediction. The workflow was applied to 213 reservoir intervals from 146 wells in the Tahe Oilfield. The results can improve the accuracy of oil-production interval prediction using well logs over conventional methods.
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Li, Xiu Hua, Rong Lei Men, Guan Wei Suo y Zheng Fang Yang. "Effect of Second Sintering on Intragranular Structure and Mechanical Properties of 10vol%Al2O3/3Y-TZP Composites". Key Engineering Materials 336-338 (abril de 2007): 1324–26. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1324.
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To study the effect of second sintering on intragranular structure and mechanical properties of 10vol%Al2O3/3Y-TZP composites, the composites were prepared by ball-milling nano-γ-Al2O3 and nano-ZrO2(3mol%Y2O3), pressing unidirectionally, cold-pressing isostatically, then first sintering at 1400°C for 2h and second sintering at 1600°C for 5h in air. The composition and microstructure of the composites were examined by X-ray diffractometer and scanning electron microscope, transmission electron microscope. The results showed that the second sintering changed the microstructure and fracture mode. After second sintering, the structure of fine grains was changed into the mixed one of large grains and small grains . Many large grains contained small grains, forming intragranular stucture that could be produced by the interblending of not only Al2O3 and ZrO2 but also ZrO2 itself. The intergranular fracture after first sintering was changed into transgranular fracture and intergranular fracture after second sintering . The second sintering led to grinds growing up and intragranular forming, which enhanced the contribution of the phase transformation toughening. Although the second sintering resulted in abnormal increase of grain size, the fracture strength and the fracture toughness of the composite were 667 MPa and 12.9 MPa⋅m1/2, respectively, due to the intragranular structure and the enhanced phase transformation toughening.
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LI, KUNJIE, FANGUI ZENG, JIANCHAO CAI, GUANGLONG SHENG, PENG XIA y KUN ZHANG. "FRACTAL CHARACTERISTICS OF PORES IN TAIYUAN FORMATION SHALE FROM HEDONG COAL FIELD, CHINA". Fractals 26, n.º 02 (abril de 2018): 1840006. http://dx.doi.org/10.1142/s0218348x18400066.
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For the purpose of investigating the fractal characteristics of pores in Taiyuan formation shale, a series of qualitative and quantitative experiments were conducted on 17 shale samples from well HD-1 in Hedong coal field of North China. The results of geochemical experiments show that Total organic carbon (TOC) varies from 0.67% to 5.32% and the organic matters are in the high mature or over mature stage. The shale samples consist mainly of clay minerals and quartz with minor pyrite and carbonates. The FE-SEM images indicate that three types of pores, organic-related pores, inorganic-related pores and micro-fractures related pores, are developed well, and a certain number of intragranular pores are found inside quartz and carbonates formed by acid liquid corrosion. The pore size distributions (PSDs) broadly range from several to hundreds nanometers, but most pores are smaller than 10[Formula: see text]nm. As the result of different adsorption features at relative pressure (0–0.5) and (0.5–1) on the N2 adsorption isotherm, two fractal dimensions [Formula: see text] and [Formula: see text] were obtained with the Frenkel–Halsey–Hill (FHH) model. [Formula: see text] and [Formula: see text] vary from 2.4227 to 2.6219 and from 2.6049 to 2.7877, respectively. Both TOC and brittle minerals have positive effect on [Formula: see text] and [Formula: see text], whereas clay minerals, have a negative influence on them. The fractal dimensions are also influenced by the pore structure parameters, such as the specific surface area, BJH pore volume, etc. Shale samples with higher [Formula: see text] could provide more adsorption sites leading to a greater methane adsorption capacity, whereas shale samples with higher [Formula: see text] have little influence on methane adsorption capacity.
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Xie, Qing-Bin, Xin Li, Chuan-Long Li y Yong-Shu Zhang. "Characteristics of Micro/Nanopores and Their Petroleum Significance in the Eastern Segment of the Altun Piedmont, Qaidam Basin, Western China". Journal of Nanoscience and Nanotechnology 21, n.º 1 (1 de enero de 2021): 181–94. http://dx.doi.org/10.1166/jnn.2021.18751.
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With continuous improvements in nanotechnology, the development of micro/nanoscale pores and fractures in reservoirs can be more clearly identified, and great progress has been made in tight sandstone and shale. Bedrock has an ultralow porosity and is a reservoir with low permeability. To study the characteristics of micro/nanoscale pore development and reveal their petroleum significance in the eastern segment of the Altun Piedmont, research has been conducted with the use of cathodoluminescence, field emission scanning electron microscopy and energy spectrum analysis, formation microresistivity image logging, high-pressure mercury injection and nuclear magnetic logging. The results have shown that the porosity of the bedrock reservoir in the eastern segment of the Altun Piedmont, as measured by helium injection and nuclear magnetic logging, is between 0.004% and 9.76%, the average porosity is between 1.663% and 3.844%, and the permeability is between the maximum of 0.002 mD and 33.239 mD. The average permeability is between 0.02 mD and approximately 3.836 mD. Micro/nanopores are generally developed, with the majority being intragranular micro/nanopores, intercrystalline micro/nanopores and microcracks, as summarized by the field emission scanning electron microscopy and energy dispersive spectroscopy analysis. Four differently sized pores develop: micropores account for approximately 20%, transition pores account for approximately 30%, and mesopores and macropores account for approximately 25% each. The pore throat development below 100 nm is greater than 50% according to the collation of experimental data from high-pressure mercury intrusion; therefore, micro/nanopores are the main storage space in the study area, and the gas logging shows good results. Micro/nanopores are also one of the main reservoir spaces of bedrock reservoirs in conjunction with the conventional reservoir space, and thus, micro/nanopores have important petroleum significance.
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Sun, Shuai y Qiang Xu. "Fabricating a Novel Intragranular Microstructure for Al2O3/GdAlO3 Ceramic Composites". Materials 11, n.º 10 (1 de octubre de 2018): 1879. http://dx.doi.org/10.3390/ma11101879.
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In order to make the embryonic form of intragranular structure, the Al2O3/GdAlO3 system was selected due to its excellent mechanical properties. Gd2O3 and Al(NO3)3·9H2O were used as the starting materials. A co-precipitation method was used for the preparation of fine ceramics and applied to synthesize the nano-powder of GdAlO3 firstly. Then, the nano-powder of GdAlO3 was mixed with the precipitates by the second co-precipitation method. After drying and calcination, the compound powder with eutectic composition (77 mol % Al3+—23 mol % Gd3+) was fast sintered by using the spark plasma sintering technique. The results revealed that the phases of the sintered samples were Al2O3 and GdAlO3. The phases showed a homogeneous and interlaced distribution. All the matrix grains were submicron. The sizes of the intragranular structures were between 50 nm and 150 nm. Therefore, the intragranular structure displayed a novel mixture of nanometer–submicron and submicron–submicron types. The different intragranular structures all changed the fracture modes of Al2O3 grains from intergranular fracture to transgranular fracture.
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Han, Wen Bo, Peng Wang y Yang Hou. "Mechanical Properties of NanoSiC Reinforced ZrB2-Based Ceramic Composite". Materials Science Forum 745-746 (febrero de 2013): 560–64. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.560.
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ZrB2-based ceramic composites were prepared through hot-pressing at a temperature of 1880°C. An intragranular microstructure was achieved because of the existence of nanoSiC. In this paper, the mechanical properties of ceramic materials of ZrB2-SiC-G were studied, and the influence of intragranular microstructure on the mechanical properties was analyzed. The values of flexural strength and fracture toughness of ZrB2-20vol%SiCnp-15vol%G reached 551.9MPa and 5.25MPa·m1/2, respectively. Compared to ZrB2-20vol%SiC-15vol%G with micro-SiC, the fracture toughness was improved.
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Zhang, Xiaoli, Caifang Wu, Jinxian He, Zeqiang Ren y Taotao Zhou. "The Controlling Effects of Compositions on Nanopore Structure of Over-Mature Shale from the Longtan Formation in the Laochang Area, Eastern Yunnan, China". Minerals 9, n.º 7 (30 de junio de 2019): 403. http://dx.doi.org/10.3390/min9070403.
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Over-mature shale has undergone complex geological processes, e.g., diagenesis, deep thermolysis, epigenesis, and metamorphism. During this series of processes, the internal components of shale are transformed coordinatively, and the special pore structure with a complex genesis in the over-mature shale is formed. The study of the special pore structure of over-mature shale and its main controlling factors can provide theoretical support for shale gas exploration and development. In this study, the over-mature shale of the Longtan Formation in the Laochang area, eastern Yunnan Province, China, was tested and analyzed to determine the total organic carbon content, kerogen microscopic composition, and its vitrinite reflectance. Moreover, the mineral composition and pore characteristics of the shale were tested using X-ray diffraction, the argon ion polishing field emission scanning electron microscopy technique, and the low temperature nitrogen adsorption experiment. The results show that the compositions of Longtan Formation shales have a low rigid clastic particles content, high clay content, and abundant metasomatic ankerite, and that the organic matter, dominated by type III, is highly mature. At the same time, the shale pore structure is characterized by a large average pore size, well-developed macropores, and a high number of micropores and mesopores. By analyzing the transformation of the mineral composition of shale during thermal evolution, the controlling factors of pore structure are determined. During the evolution of shale, the intergranular pores (mainly large pores) between rigid minerals are destroyed in large quantities. After a short period, a large number of dissolved pores with the pore size of macropores are formed in the acid-resistant minerals under the action of organic acid. These dissolved pores, together with the remaining intergranular pores of rigid minerals and micro-fractures, form most of the macropores of shale. There is a large amount of ankerite in over-mature shale formed during metasomatism, which occludes some pores of shale. However, intragranular pores and cleavage-sheets develop in ankerite, contributing some porosity to the shale reservoir. Inter-clay pores and organic matter pores constitute most shale micro and mesopores, and between which inter-clay pores take dominance.
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He, Wen, Yun Long Ai, Chang Hong Liu, Jian Ping Zhang y Jia Yuan Ding. "Microstructure and Properties of Al2O3-ZrO2(n) Composite Ceramics Prepared by Microwave Sintering". Advanced Materials Research 177 (diciembre de 2010): 364–68. http://dx.doi.org/10.4028/www.scientific.net/amr.177.364.
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Al2O3-ZrO2(n) composite ceramics were prepared by microwave sintering. The properties and microstructure were investigated, including vickers hardness, fracture toughness, bending strength, wear resistance and heat-shocking resistance. The results show that the properties and microstructure of alumina matrix ceramics are affected by the addition of nano-ZrO2 particles. When the content of ZrO2 is 15vol%, the hardness, fracture toughness and bending strength of the Al2O3-ZrO2 composites reach maximum values 13350MPa, 6.41MPa•m1/2 and 502MPa, respectively. The wear resistance of alumina matrix ceramics are improved only on the condition of adding an appropriate amount of nano-ZrO2. The wear mechanism of the composites are abrasive particle wear and adhesion wear co-existing. The crack propagation rate of Al2O3 matrix ceramics decreases remarkably with the addition of nano-ZrO2 particles. The mechanisms of ZrO2 improving the heat-shocking resistance of alumina matrix ceramics are mainly phase transfer toughening. Nano-ZrO2 particles exist in the intragranular and grain boundary of alumina matrix ceramics, and exist intragranular structures.
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Zhang, F. C., H. H. Luo, T. S. Wang, M. Zhang y Y. N. Sun. "Stress state and fracture behavior of alumina–mullite intragranular particulate composites". Composites Science and Technology 68, n.º 15-16 (diciembre de 2008): 3245–50. http://dx.doi.org/10.1016/j.compscitech.2008.08.012.
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Chung, Dong-Seok, J. K. Kim y Manabu Enoki. "In-Situ Fabrication and Fracture Characteristics of Structural Gradient Ni/Ni-Aluminide//Ti/Ti-Aluminide Layered Materials". Materials Science Forum 475-479 (enero de 2005): 1521–24. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1521.
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Ni/Ni-aluminide//Ti/Ti-aluminide laminate composite, considered as a functionally gradient material, was manufactured by thin foil hot press technique. Thick intermetallic layers of NiAl and TiAl3 were formed by a self-propagating high-temperature synthesis (SHS) reaction, and thin continuous layers of Ni3Al and TiAl were formed by a solid-state diffusion. Fracture resistance with loading along the crack arrester direction is higher than crack divider direction due to the interruption of crack growth in metal layers. The Ni3Al and NiAl intermetallic layer showed cleavage and intergranular fracture behavior, respectively, while the fracture mode of TiAl3 layer was found to be a intragranular cleavage. The debonding between metal and intermetallic layer and the pores were observed in the Ni/Ni-aluminide layers, resulting in the lower fracture resistance.
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Zhang, Wen Lai, Xin Wang, Chao Hong Liu, Gui Jun Jiang y Qiu Ju Zheng. "Grinding Characteristics and Removal Mechanisms of LaPO4/Al2O3 Micro-Nano Composite Ceramics". Advanced Materials Research 306-307 (agosto de 2011): 774–77. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.774.
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In this paper, the prepared LaPO4/Al2O3composite ceramics were ground by the surface grinding machine. The phase composition and morphology of the coated powders as well as the microstructure of grinding surface of the ceramics were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM), respectively. The results show that the coated powders have a distinct core-shell structure which has a great effect on material’s removal approaches. The main fracture mode is caused by intragranular fracture of layered LaPO4rather than the weak interface. Besides, the primary grinding removal mechanism of LaPO4/Al2O3composite ceramics mainly rise from cracks propagating along the interlayer of LaPO4.
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Xu, Chong Hai, M. D. Yi, Z. Y. Jiang, J. J. Zhang y G. C. Xiao. "Preparation of an Advanced Al2O3 Based Nanocomposite Ceramic Die Material". Materials Science Forum 628-629 (agosto de 2009): 465–70. http://dx.doi.org/10.4028/www.scientific.net/msf.628-629.465.
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Through the incorporation of nano sized Titanium Carbonitride powders into the Al2O3 matrix, an advanced Al2O3/Ti(C7N3) nanocomposite ceramic die material was fabricated by vacuum hot pressing technique. Effects of the content of nano Ti(C7N3) on the microstructure and mechanical properties of the nanocomposite ceramic die material were investigated. It indicates that both flexural strength and fracture toughness were increased noticeably compared with the pure micrometer sized alumina ceramic. Toughening mechanisms of the ceramic composite were also analyzed. It reveals that the intragranular/intergranular microstructures and the resulted transgranular/intergranular fracture modes are the main causes for the reinforcing and toughening of the nanocomposite ceramic die material.
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Zhao, Dajun, Shulei Zhang y Meiyan Wang. "Microcrack Growth Properties of Granite under Ultrasonic High-Frequency Excitation". Advances in Civil Engineering 2019 (18 de junio de 2019): 1–11. http://dx.doi.org/10.1155/2019/3069029.
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The failure of most rock materials is essentially a process of crack initiation and propagation. It is of great significance to study the microcrack growth characteristics of granite under ultrasonic high-frequency excitation for understanding the failure mechanism of rock under ultrasonic vibration. In this paper, the experimental and numerical simulation methods are used to study the propagation characteristics of rock cracks under ultrasonic vibration. Scanning electron microscopy (SEM) was used to observe the growth of microcracks in granite samples after ultrasonic vibration for 0 min, 2 min, and 4 min. A discrete element software PFC2D was used to simulate and solve the cracking mechanism of rock cracks under ultrasonic vibration. Also, it is found that the action of ultrasonic vibration can effectively promote the development of microcracks in the granite samples. The main three cracks causing the failure of quartz under the ultrasonic high frequency are intragranular cracks, transgranular cracks, and grain boundary cracks. The breakage of transgranular cracks usually contributes a shell-like fracture, that is, a regular curved surface with a concentric circular pattern appears on the fracture surface, which is a typical quartz brittle fracture mode. In addition, the feldspar grain failure is mainly caused by intragranular crack and transgranular crack. Microcracks are wavy expansion in feldspar grain. Mica failure is mainly caused by grain boundary crack, and the effect of lamellar cleavage on the failure of mica is significant. Moreover, it is also found that the mechanism of microcrack propagation is tensile failure. The failure of feldspar grains is mainly contributed to the failure of granite.
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Sakuma, Takaaki, Yoshinobu Motohashi, Taiju Shibata, Kazuhiro Sawa y Masahiro Ishihara. "Microstructures after Bending Deformations to Fracture of Zr Ion Irradiated Superplastic Ceramic 3Y-TZP". Materials Science Forum 551-552 (julio de 2007): 475–80. http://dx.doi.org/10.4028/www.scientific.net/msf.551-552.475.
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The effects of Zr ion irradiation on the mechanical properties of a typical superplastic ceramic, 3mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP), were examined and discussed. The specimens were irradiated by Zr11+ ions with 130MeV at fluence level of 3.5×1012 and 2.1×1013 ions/cm2 in the TANDEM accelerator at Tokai Reasearch Establishment of JAEA. Microstructures after annealing and bending deformations to fracture of Zr ion irradiated 3Y-TZP were examined. It was found that the ratio of intergranular fracture to intragranular fracture was increased in the region that was affected by Zr ion irradiation. It seemed that grain boundary cohesion became relatively weak in the irradiated surface region. The influence of Zr ion irradiation on the mechanical properties almost disappeared when the irradiated 3Y-TZP was subsequently heated to 1173K.
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Mitra, Biplob, Jon Hilden y James Litster. "Assessment of Intragranular and Extragranular Fracture in the Development of Tablet Tensile Strength". Journal of Pharmaceutical Sciences 107, n.º 10 (octubre de 2018): 2581–91. http://dx.doi.org/10.1016/j.xphs.2018.05.011.
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Wu, Hui Bin, Guo Li Liang, Y. H. Wen y C. C. Yang. "In Situ Study of Fracture Process for B-Class Shipbuilding Steel". Materials Science Forum 704-705 (diciembre de 2011): 1310–15. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.1310.
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Crack initiation, propagation and microfracture processes of B-class shipbuilding steel have been investigated by using an in-situ tensile stage installed inside a scanning electron microscope chamber, meanwhile the secondary crack propagation at low temperature brittle fracture has also been studied. It is revealed that micro cracks always nucleated at the notch of specimens due to the stress concentration and then propagate along the interface of ferrite-pearlite. The plastic deformation of polygonal ferrite occurred in the loading process, the cracks propagated as “Z” morphology in the matrix. In the low temperature brittle fracture zone, the secondary crack propagated through the ferrite matrix in the manner of transgranular crack. When the secondary crack propagated to pearlite region, the intragranular crack and transgranular crack were observed in the pearlite region .
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Cheng, P. M., G. J. Zhang, J. Y. Zhang, G. Liu y J. Sun. "Coupling effect of intergranular and intragranular particles on ductile fracture of Mo–La2O3 alloys". Materials Science and Engineering: A 640 (julio de 2015): 320–29. http://dx.doi.org/10.1016/j.msea.2015.05.032.
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Ariyoshi, Kingo y Nan Ukumori. "Intragranular Fracture Mechanism of Highly Crystalline Lithium Manganese Oxide during Lithium Insertion/Extraction Reactions". ACS Applied Energy Materials 4, n.º 8 (28 de julio de 2021): 8142–49. http://dx.doi.org/10.1021/acsaem.1c01442.
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Xiao, Fei, Jianguo Yang, Shichao Li, Fanhao Gong, Jian Zhang, Yulai Yao, Ang Li et al. "Geological and Geochemical Characteristics of the First Member of the Cretaceous Qingshankou Formation in the Qijia Sag, Northern Songliao Basin, Northeast China: Implication for Its Shale Oil Enrichment". Geofluids 2021 (12 de agosto de 2021): 1–20. http://dx.doi.org/10.1155/2021/9989792.
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The Qijia Sag, a secondary tectonic unit in the northern Songliao Basin, developed plentiful shale oil resources in the first member of the Cretaceous Qingshankou Formation (K2qn1) as its main target layer. However, the systematic study on the geological and geochemical characteristics of K2qn1 in the sag has not been carried out. Taking the core samples from the SYY1 well covering the whole K2qn1 as the main study object and concerning some relevant intervals from the SYY1HF well and other earlier wells, petrologic features, organic geochemical characteristics, oil-bearing property, and reservoir characteristics of K2qn1 were analyzed in detail. The results show that the lithology of K2qn1 is mainly dark mudstone genera accounting for more than 90% of the formation thickness with few macrostructural fractures, indicating that K2qn1 developing in deep to semideep lacustrine facies of the Qijia Sag belongs to the typical matrix reservoirs for shale oil. According to lithology features and logging curves, K2qn1 can be divided into three submembers consisting of K2qn11, K2qn12, and K2qn13 from above to below. Compared to the K2qn11 submember, the K2qn12 and K2qn13 submembers obviously are more enriched in shale oil, which is supported by the following three aspects: (i) the average TOC (total organic carbon) values of K2qn11, K2qn12, and K2qn13 are 1.96%, 2.42%, and 2.72%, respectively. The organic matter types of K2qn12 and K2qn13 are mainly type I and type II1, while those of K2qn11 are mainly type II1 and type II2. K2qn1 is at the end of the oil window with a R o (vitrinite reflectance) average of 1.26%, and the maturity of K2qn12 and K2qn13 is slightly higher than that of K2qn11. (ii) The average OSI (oil saturation index) values of K2qn11, K2qn12, and K2qn13 are 110.54 mg/g, 171.74 mg/g, and 150.87 mg/g, respectively, which all reach the zone of oil crossover. The saturated hydrocarbon of EOM (extractable organic matter) in K2qn12 and K2qn13 is of higher content than that in K2qn11, while it is the opposite for the aromatic hydrocarbon, nonhydrocarbon, and asphaltene, indicating better oil mobility for K2qn12 and K2qn13. The average oil saturation values of K2qn11, K2qn12, and K2qn13 are 24.77%, 32.86%, and 35.54%, respectively. (iii) The intragranular dissolution pores and organic pores in K2qn12 and K2qn13 are more developed than those in K2qn11. The average effective porosity values of K2qn11, K2qn12, and K2qn13 interpreted from NMR logging are 4.88%, 6.26%, and 5.86%, respectively. Based on the above-mentioned analyses, the lower K2qn12 and the upper K2qn13 are determined as the best intervals of shale oil enrichment for K2qn1 vertically in the Qijia Sag. There is a certain horizontal heterogeneity of TOC, S 1 , and effective porosity in the drilling horizontal section of K2qn1 of the SYY1HF well. Therefore, the lower K2qn12 and the upper K2qn13 in the area with relatively weak horizontal reservoir heterogeneity of the study area should be selected as the preferential targets for shale oil exploration.
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Zhou, You, Kiyoshi Hirao, Motohiro Toriyama y Hidehiko Tanaka. "Silicon carbide ceramics prepared by pulse electric current sintering of β–SiC and α–SiC powders with oxide and nonoxide additives". Journal of Materials Research 14, n.º 8 (agosto de 1999): 3363–69. http://dx.doi.org/10.1557/jmr.1999.0455.
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Using a pulse electric current sintering (PECS) method, β–SiC and α–SiC powders doped with a few weight percent of Al2O3–Y2O3oxide or Al4C3–B4C–C nonoxide additives were rapidly densified to high densities (95.2–99.7%) within less than 30 min of total processing time. When Al2O3–Y2O3additive was used, both ceramics resulting from β–SiC and α–SiC had fine, equiaxed microstructures. In contrast, when Al4C3–B4C–C additive was used, the ceramic resulting from α–SiC had a coarse, equiaxed microstructure, whereas the ceramic resulting from β–SiC was composed of large elongated grains whose formation was accompanied by the β →?α phase transformation of SiC. Compared with the Al2O3–Y2O3-doped SiC ceramics, the Al4C3–B4C–C-doped SiC ceramics had higher densities, lower fracture toughness, and higher hardness. The fracture mode of the oxide-doped SiC was mainly intergranular, whereas the nonoxide-doped SiC exhibited almost complete intragranular fracture that was attributed to the higher interfacial bonding strength.
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Wang, Xiangzeng. "Characteristics of Chang 7 shale gas in the Triassic Yanchang Formation, Ordos Basin, China". Interpretation 5, n.º 2 (31 de mayo de 2017): SF31—SF39. http://dx.doi.org/10.1190/int-2016-0086.1.
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The Yanchang Formation in the Ordos Basin in North Central China represents a large, long-lived lacustrine system of the late Triassic Period. The extensive shales within this system provide hydrocarbons (HCs) for conventional and unconventional oil and gas reservoirs. In the formation, the Chang 7 shale is the thickest shale with the best geochemical parameters, and it is the main source rock in this area. In recent years, the discovery of shale gas in the Chang 7 shale has promoted the exploration and development of lacustrine shale gas in China. We have estimated the shale gas resource potential based on the analysis of the geologic conditions of the Chang 7 shale. The average thickness of the Chang 7 shale reaches 42.6 m, and the main organic matter types are types [Formula: see text] and [Formula: see text]. The average content of organic carbon is more than 3%, and the average HC potential is [Formula: see text]. However, the thermal maturity of the Chang 7 shale is low with a vitrinite reflectance [Formula: see text] ranging from 0.83% to 1.10%. The Chang 7 shale lithology consists of shale and sandy laminations or thin sandstones. The shale is characterized by high clay mineral content and poor porosity and permeability, with an average porosity of 1.8% and an average permeability of [Formula: see text]. The sandy laminations or thin sandstones are characterized by relatively higher brittle mineral content, relatively lower clay mineral content, and higher porosity and permeability. The pores of the Chang 7 shale include primary intergranular and intragranular pores, secondary intragranular and intragranular dissolved pores, fracture pores, and organic-matter-hosted pores. The proportion of adsorbed gas, free gas, and dissolved gas is approximately 52%, 37%, and 11%, respectively, and the shale gas resources of the Chang 7 shale are [Formula: see text].
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Xiao, Guang Chun, Chong Hai Xu, Zhao Qiang Chen, Bin Fang y Gao Feng Wei. "Research on the Hot Pressing Parameters of Ti (C,N)/Al2O3 Nanocomposite Ceramic Die Material and the Material Fabrication". Key Engineering Materials 589-590 (octubre de 2013): 594–99. http://dx.doi.org/10.4028/www.scientific.net/kem.589-590.594.
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In the present study, Ti (C,N)/Al2O3nanocomposite ceramic die material was fabricated through adding nanosize Ti (C,N) powders into micrometer Al2O3matrix by vacuum hot-pressing technology. Effects of the hot press sintering process on mechanical property and microstructure of the nanocomposite ceramic die material were investigated. The optimum hot-pressing technology with the sintering temperature of 1650°C, time duration of 15min and pressure of 30MPa was achieved. The microstructural morphology of the material was also analyzed. It reveals that the intergranular/intragranular microstructure and the resulted intergranular/transgranular fracture mode are the main causes for strengthening and toughening in the nanocomposite ceramic die material.
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Pei, Lin Qing, Cheng Lu, Kiet Tieu, Hong Tao Zhu, Xing Zhao, Kui Yu Cheng y Liang Zhang. "A Molecular Dynamics Simulation of Fracture in Nanocrystalline Copper". Journal of Nano Research 23 (julio de 2013): 50–56. http://dx.doi.org/10.4028/www.scientific.net/jnanor.23.50.
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A large-scale molecular dynamics simulation was used to investigate the propagation of cracks in three dimensional samples of nanocrystalline copper, with average grain sizes ranging from 5.34 to 14.8 nm and temperatures ranging from 1K to 500 K. It was shown that intragranular fracture can proceed inside the grain at low temperature, and plastic deformation around the tip of the crack is accommodated by dislocation nucleation/emission; indeed, both fully extended dislocation and deformation twinning were visible around the tip of the crack during fracture. In addition, due to a higher concentration of stress in front of the crack at a relative lower temperature, it was found that twinning deformation is easier to nucleate from the tip of the crack. These results also showed that the decreasing grain size below a critical value exhibits a reverse Hall-Petch relationship due to the enhancing grain boundary mediation, and high temperature is better for propagating ductile cracks.
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Yang, Shang Lei y Qing Lin Lin. "Microstructures and Properties of the Al-4.5Zn-1.5Mg-0.5Mn Aluminum Alloy Welding Joints". Advanced Materials Research 148-149 (octubre de 2010): 640–43. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.640.
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The Al-4.5Zn-1.5Mg-0.5Mn aluminum alloy was welded by MIG welding in test, and the microstructure and mechanical property of joint were investigated. The results of experimentation show that the microstructure of welding metal is as-cast microstructure, and the microstructure of base metal is isometric crystal. There is a narrow fusion zone near the edge of weld seam, which consists of fine columnar grains. In the base metal and heat affected zone, the precipitation was diffuse in the intragranular, while strengthening phase η mainly focused on grain boundaries. The precipitation phases in the heat-affected zone distributed unevenly with large size, intermittent and segregation. In the welding metal, there is no precipitation phase. The microhardness on center of welding metal is lowest in joint. The tensile strength of welding joint is 272MPa, and the percentage elongation after fracture is 6.6%. The zone of fracture is located in the welding metal.
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Stanculescu, Roxana, Nadejda Horchidan, Carmen Galassi, Mihai Asandulesa, Leontin Padurariu, Cristina Ciomaga y Liliana Mitoseriu. "Porous (Ba,Sr)TiO3 ceramics for tailoring dielectric and tunability properties: Modelling and experiment". Processing and Application of Ceramics 11, n.º 4 (2017): 235–46. http://dx.doi.org/10.2298/pac1704235s.
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3D Finite Element Method simulations were employed in order to describe tunability properties in anisotropic porous paraelectric structures. The simulations predicted that properties of a ceramic can be tailored by using various levels of porosity. Porous Ba0.6Sr0.4TiO3 (BST) ceramics have been studied in order to investigate the influence of porosity on their functional properties. The BST ceramics with various porosity levels have been obtained by solid-state reaction. Lamellar graphite in different concentration of 10, 20 and 35 vol.%was added as sacrificial pore forming agent. The structural, microstructural, dielectric and tunability properties were investigated. By comparison with dense BST ceramic, porous samples present a fracture mode transformation from intragranular to an intergranular fracture and a decrease of grain size. Lower dielectric constants, low dielectric losses, but higher values of tunability than in the dense material were obtained in the porous BST structures as a result of local field inhomogeneity generated by the presence of air pores-ceramic interfaces.
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Kashif, Muhammad, Yingchang Cao, Guanghui Yuan, Muhammad Asif, Kamran Javed, Jose Nicanor Mendez, Danish Khan y Lin Miruo. "Pore size distribution, their geometry and connectivity in deeply buried Paleogene Es1 sandstone reservoir, Nanpu Sag, East China". Petroleum Science 16, n.º 5 (25 de septiembre de 2019): 981–1000. http://dx.doi.org/10.1007/s12182-019-00375-3.
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Abstract The study of pore characteristics is of great importance in reservoir evaluation, especially in deeply buried sandstone. It controls the storage mechanism and reservoir fluid properties of the permeable horizons. The first member of Eocene Shahejie Formation (Es1) sandstone is classified as feldspathic litharenite and lithic arkose. The present research investigates the pore characteristics and reservoir features of the deeply buried sandstone reservoir of Es1 member of Shahejie Formation. The techniques including thin-section petrography, mercury injection capillary pressure (MICP), scanning electron microscopy and laser scanning confocal microscope images were used to demarcate the pores including primary intergranular pores and secondary intergranular, intragranular, dissolution and fracture pores. Mercury injection test and routine core analysis were led to demarcate the pore network characteristics of the studied reservoir. Pore size and pore throat size distribution are acquired from mercury injection test. Porosity values range from 0.5% to 30%, and permeability ranges 0.006–7000 mD. Pore radii of coarse-grained sandstone and fine-grained sandstone range from 0.2 to > 4 µm and 1 nm to 1.60 µm, respectively, by MICP analysis. The mineral composition also plays an important role in protecting the pores with pressure from failure. Fractured sandstone and coarse-grained sandstone consist of large and interconnected pores that enhance the reservoir porosity and permeability, whereas fine-grained sandstone and siltstone consist of numerous pores but not well interconnected, and so they consist of high porosity with low permeability.
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Li, Jian Hua. "Characterization of ZrO2/PZT Nanocomposites Ceramics Prepared by the Citrate Precursor Route". Materials Science Forum 852 (abril de 2016): 407–10. http://dx.doi.org/10.4028/www.scientific.net/msf.852.407.
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Lead zirconate titanate (PZT)-based nanocomposites embedded with ZrO2 nanoparticles were fabricated by citrate precursor route from metastable phases in situ. The effect of ZrO2 content on mechanical and piezoelectric properties of composites was investigated. m-ZrO2 particles covering 30-70 nm are dispersed homogenously inside the PZT matrix grain with stress strips around m-ZrO2 nanoparticles. The fracture mode changes from intergranular to intragranular with increasing the amount of ZrO2. Transformation toughening and nanoparticle dispersion toughening of ZrO2 contributed to the reinforcement of the PZT/ZrO2 nanocomposites. It is exciting to found that the mechanical properties as well as the piezoelectric properties were both increased compared with those of monolithic PZT when add a certain amount of ZrO2.
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Todd, Richard I. y Apichart Limpichaipanit. "Microstructure-Property Relationships in Wear Resistant Alumina/SiC "Nanocomposites"". Advances in Science and Technology 45 (octubre de 2006): 555–63. http://dx.doi.org/10.4028/www.scientific.net/ast.45.555.
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Alumina/SiC “nanocomposites” consist of a dispersion of SiC “nanoparticles” in an alumina matrix with conventional grain size. The nanocomposites are much more resistant to severe wear than pure alumina and this paper explores the mechanisms responsible by examining microstructure-property relationships. Results correlating (i) microstructure, (ii) wear rate in a simple abrasive wear test and (iii) quantitative analysis of the appearance of the worn surfaces, are presented. The results show that the reduction in wear rate caused by the SiC is a consequence of the reduction in surface pullout by brittle fracture only. For small volume fractions ( 5vol%), the main effect of the SiC additions is to reduce the dimensions (diameter, depth) of the individual pullouts. This is suggested to be a consequence of the change in fracture mode from intergranular in alumina to transgranular in the nanocomposites. For greater additions of SiC nanoparticles (10vol%), the brittle fracture responsible for the cracking is also suppressed, and it is proposed that this is a consequence of the blocking of the formation of the long twins or dislocation pileups that are thought to be responsible for crack initiation by intragranular SiC particles (i.e. a form of slip homogenisation).
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Reali, Luca, Saïd El Chamaa, Daniel S. Balint, Catrin M. Davies y Mark R. Wenman. "Deformation and fracture of zirconium hydrides during the plastic straining of Zr-4". MRS Advances 5, n.º 11 (2020): 559–67. http://dx.doi.org/10.1557/adv.2020.145.
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ABSTRACTCrack initiation in zirconium alloys is an important issue for the safety of water-cooled fission reactors. Zirconium hydrides that precipitate in service are potential crack nucleation sites. In this work, the deformation and cracking of zirconium hydrides was studied during room temperature deformation of a Zircaloy-4 tensile sample up to fracture. The sample contained a hydrogen concentration of 100 ± 20 ppm. The main aims of this study were to better understand the mechanisms behind the hydride fracture in a polycrystalline matrix, and to identify at which point in the deformation of the Zr matrix the first hydrides break. Cracks thus nucleated may coalesce and propagate through the hydrided Zr-alloy. Scanning electron microscopy (SEM) images of a number of hydrides, both intergranular and intragranular, were taken at discrete increments of deformation during an interrupted tensile test. The results show that cracks in hydrides tend to always occur normal to the applied load, signalling the importance of the external stress. However, evidence is also provided to support the hypothesis that internal stresses generated by microstructural constraints may lead to the fracture of some intergranular hydrides.
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Pieczara, Łukasz. "Influence of Structural Features and Fracture Processes on Surface Roughness: A Case Study from the Krosno Sandstones of the Górka–Mucharz Quarry (Little Beskids, Southern Poland)". Studia Geotechnica et Mechanica 37, n.º 3 (1 de septiembre de 2015): 85–93. http://dx.doi.org/10.1515/sgem-2015-0036.
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Abstract The paper presents the results of analysis of surface roughness parameters in the Krosno Sandstones of Mucharz, southern Poland. It was aimed at determining whether these parameters are influenced by structural features (mainly the laminar distribution of mineral components and directional distribution of non-isometric grains) and fracture processes. The tests applied in the analysis enabled us to determine and describe the primary statistical parameters used in the quantitative description of surface roughness, as well as specify the usefulness of contact profilometry as a method of visualizing spatial differentiation of fracture processes in rocks. These aims were achieved by selecting a model material (Krosno Sandstones from the Górka-Mucharz Quarry) and an appropriate research methodology. The schedule of laboratory analyses included: identification analyses connected with non-destructive ultrasonic tests, aimed at the preliminary determination of rock anisotropy, strength point load tests (cleaved surfaces were obtained due to destruction of rock samples), microscopic analysis (observation of thin sections in order to determine the mechanism of inducing fracture processes) and a test method of measuring surface roughness (two- and three-dimensional diagrams, topographic and contour maps, and statistical parameters of surface roughness). The highest values of roughness indicators were achieved for surfaces formed under the influence of intragranular fracture processes (cracks propagating directly through grains). This is related to the structural features of the Krosno Sandstones (distribution of lamination and bedding).
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Hajilou, T., Y. Deng, N. Kheradmand y A. Barnoush. "Hydrogen enhanced cracking studies on Fe–3wt%Si single and bi-crystal microcantilevers". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, n.º 2098 (12 de junio de 2017): 20160410. http://dx.doi.org/10.1098/rsta.2016.0410.
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Hydrogen (H) enhanced cracking was studied in Fe–3wt%Si by means of in situ electrochemical microcantilever bending test. It was clearly shown that the presence of H causes hydrogen embrittlement (HE) by triggering crack initiation and propagation at the notch where stress concentration is existing. Additionally, the effect of carbon content and the presence of a grain boundary (GB) in the cantilever were studied. It was shown that in the presence of H the effect of carbon atom on pinning the dislocations is reduced. On the other hand, the presence of a GB, while the chemical composition of material kept constant, will promote the HE. Crack initiation and propagation occur in the presence of H, while the notch blunting was observed for both single and bi-crystalline beams bent in air. Post-mortem analysis of the crack propagation path showed that a transition from transgranular fracture to intragranular fracture mechanism is highly dependent on the position of the stress concentration relative to the GB. This article is part of the themed issue ‘The challenges of hydrogen and metals’.
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Zhao, Liang, Shuang Yao y Jing Du. "Modification Effect of Nanometre Zirconia on Ca-PSZ Ceramics". Materials Science Forum 953 (mayo de 2019): 59–64. http://dx.doi.org/10.4028/www.scientific.net/msf.953.59.
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The modified calcium oxide partially stabilized zirconia ceramics were fabricated using ZrO2 powder as raw materials, CaO as stabilizer, and nanometre zirconia as modification agent. The relationship between additive amount of nanometre zirconia and the performance of Ca-PSZ ceramics were researched via testing the physical properties, analyzing mineral phase composition, and observing microstructure of the samples. The results show that the introduction of nanometre zirconia powder has a significant effect on the physical properties of Ca-PSZ, with an addition of 8wt%, bulk density was up to 5.08 g/cm3, and the compressive strength reached 381 MPa. Compared with the unmodified Ca-PSZ sample, the porosity of the modified Ca-PSZ samples decreased by 40%, and the compressive strength increased by 70%. The introduction of nanometre zirconia has an inhibitory effect on the abnormal growth of zirconia grains and improves the densification of the Ca-PSZ ceramics. Through the formation of intragranular structure, nanometre zirconia can induce transgranular fracture and weaken crystalline fracture, thereby increasing the strength of the Ca-PSZ ceramics.
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Engel, Jutta, Vassili F. Pastushenko, Walter Richter y Edwin Donath. "On the interaction between chromaffin granule membranes and intragranular vesicles – Theory and analysis of freeze-fracture micrographs". Biorheology 28, n.º 1-2 (1 de marzo de 1991): 75–87. http://dx.doi.org/10.3233/bir-1991-281-208.
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Zhang, You Feng, Qing Chang Meng, De Chang Jia y Yu Zhou. "Effects of Polarization Treatment on Mechanical Properties of Al2O3/LiTaO3 Composite Ceramics". Key Engineering Materials 353-358 (septiembre de 2007): 1314–17. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1314.
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The Al2O3/LiTaO3 (ALT) composite ceramics were fabricated by hot pressing method and polarization treated at different temperatures along height and width directions. Effects of polarization treatment on mechanical properties of the ALT composite ceramic were investigated. Flexural strength decreased with the increase of polarization temperature. Meanwhile, the flexural strength of samples polarized in height direction is higher than that polarized in width direction. The composite ceramic fractures intragranularly, and many rupture steps in polarization direction were observed on fractographs of the composite ceramics. Domain switching in LiTaO3 particles increased the resistance of crack propagation and improved the mechanical properties of the polarized ALT composite ceramics.
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He, Lin, Chuan Zhen Huang, Jing Sun y Han Lian Liu. "Microstructure and Mechanical Properties of Ti(C,N)-ZrO2-Ni-Mo Composite Cermet". Materials Science Forum 471-472 (diciembre de 2004): 348–52. http://dx.doi.org/10.4028/www.scientific.net/msf.471-472.348.
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Ti(C0.7N0.3)-ZrO2-Ni-Mo cermet with 73.9%Ti(C0.7N0.3)-10%ZrO2-13%Ni-3.3%Mo(in mass) was fabricated by HP technology. The fabricated material possesses good mechanical properties with flexure strength (1264.4Mpa), fracture toughness (15 MPa.m1/2) and Vickers hardness (16.2GPa). The results of microstructure observation and analyses of the composite cermet by TEM, SEM and EDAX show that Mo2C nanoparticles are separated in the Ti(C,N) grains and the structure is similar to the “intragranular structure” in nanocomposite material. Smaller size t-ZrO2 and m-ZrO2 grains are distributed o n the boundaries of Ti(C,N) grains and the amount of m-ZrO2 is more than that of t-ZrO2.The growth of m-ZrO2 grain has an orientation on Ti(C,N) grain, which is propitious to the boundary bonding strength.