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Gotowe bibliografie tematyczne / Brittle and ductile rock

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Gotowa bibliografia na temat „Brittle and ductile rock”

Autor: Grafiati

Data publikacji: 6 września 2023

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Artykuły w czasopismach na temat "Brittle and ductile rock"

1

Karato, Shun-ichiro, i Teng-fong Wong. "Rock deformation: Ductile and brittle". Reviews of Geophysics 33 (1995): 451. http://dx.doi.org/10.1029/95rg00178.

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Culshaw, Nicholas, i Carla Dickson. "Cape St. Marys shear zone and the Halifax Group – Rockville Notch Group disconformity, southwestern Nova Scotia: structural development and tectonic significance". Canadian Journal of Earth Sciences 52, nr 10 (październik 2015): 921–37. http://dx.doi.org/10.1139/cjes-2015-0007.

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The Cape St. Marys shear zone, situated in a corridor of Alleghanian reworking in the southwestern Meguma terrane, contains the deformed, discordant contact of Lower Ordovician slate of the Halifax Group with the Silurian White Rock Formation. Close to the contact, the Alleghanian cleavage (S2) is parallel to the contact in both units, with S0 in the White Rock Formation metavolcanic rocks and Halifax slate parallel to and discordant to the contact. The geometry of deformed Neoacadian minor folds, quartz fringes on sulphide grains, and micro-porphyroclasts demonstrate thrust-sense shear (White Rock Formation over Halifax slate). Pure shear and volume loss are inferred as components of the strain path from S2 microstructure and estimates of strain in the Halifax slate. Estimates of shear strain imply moderate displacements within the Cape St. Marys shear zone during deformation of the northwestern limb of the Cape St. Marys syncline. The discordant contact of the Halifax slate with the White Rock formation cannot be a thrust plane because younger rocks overlie older rocks. Thus the contact is what it appears to be: an angular unconformity embedded within a ductile shear zone. Brittle-ductile faults, quartz vein arrays, and centimetre-scale kink bands disturb S2 in the Halifax slate a few metres northwest of the contact. The geometry of the brittle-ductile structures and the orientation of stretching lineation in the ductile structures link the episodes kinematically. Quartz veins accompanying brittle-ductile deformation suggest that fluids derived during pressure solution development of S2 drove the change from ductile to brittle-ductile deformation in the Cape St. Marys shear zone during the latter stages of convergence. In a regional context, the moderate shear values of the Cape St. Marys shear zone are reasonable for the diminishing displacement expected near the termination of a northwest-propagating regional shear system. Whereas the transition from ductile to brittle-ductile deformation occurred late in the development of the Cape St. Marys shear zone, brittle-ductile structures were dominant closer to the northwest border of the zone of Alleghanian deformation. The fluids required for the transition may have been driven along a pressure gradient from more internal parts of the corridor, where pressure solution was more active.

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Nichol, Susan L., Oldrich Hungr i S. G. Evans. "Large-scale brittle and ductile toppling of rock slopes". Canadian Geotechnical Journal 39, nr 4 (1.08.2002): 773–88. http://dx.doi.org/10.1139/t02-027.

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Slow, ductile toppling of rock masses commonly creates large-scale mountain slope deformations. In some cases, rock toppling can initiate an extremely rapid catastrophic landslide. This theoretical and field-based study was aimed at distinguishing the two alternative modes of toppling. The idea that certain key parameters of the undeformed rock mass may influence failure behaviour in a quantifiable way was examined through a parametric study of a large rock slope using the universal distinct element code (UDEC). The slope was modelled using variations of rock mass strength, discontinuity orientation and persistence, and toe over-steepening. The results indicated two distinct types of failure behaviour: (i) ductile, self-stabilizing flexural toppling in weak rock with a single dominant joint set; and (ii) brittle, catastrophic block toppling in strong rock containing persistent, down-slope oriented or horizontal cross-joints, which act as surfaces of separation at the base of the toppling blocks. The two mechanisms exhibit very different patterns of prefailure stress. During flexural toppling, the major principal stress is oriented predominantly parallel with the slope surface. In the case of block toppling, it is vertical and a large part of the unstable volume is horizontally destressed. Boundaries between the two types of behaviour have been approximately mapped. Two field case studies were then examined in light of the results. The first case involves a block topple in strong granitic rocks that failed catastrophically and produced a high velocity rock avalanche; and the second case is a large flexural topple in metamorphic rocks, exhibiting slow deformations.Key words: rock toppling, landslide, distinct element model, parametric study, hazard assessment.

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Wenning, Quinn C., Claudio Madonna, Antoine de Haller i Jean-Pierre Burg. "Permeability and seismic velocity anisotropy across a ductile–brittle fault zone in crystalline rock". Solid Earth 9, nr 3 (29.05.2018): 683–98. http://dx.doi.org/10.5194/se-9-683-2018.

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Abstract. This study characterizes the elastic and fluid flow properties systematically across a ductile–brittle fault zone in crystalline rock at the Grimsel Test Site underground research laboratory. Anisotropic seismic velocities and permeability measured every 0.1 m in the 0.7 m across the transition zone from the host Grimsel granodiorite to the mylonitic core show that foliation-parallel P- and S-wave velocities systematically increase from the host rock towards the mylonitic core, while permeability is reduced nearest to the mylonitic core. The results suggest that although brittle deformation has persisted in the recent evolution, antecedent ductile fabric continues to control the matrix elastic and fluid flow properties outside the mylonitic core. The juxtaposition of the ductile strain zone next to the brittle zone, which is bounded inside the two mylonitic cores, causes a significant elastic, mechanical, and fluid flow heterogeneity, which has important implications for crustal deformation and fluid flow and for the exploitation and use of geothermal energy and geologic waste storage. The results illustrate how physical characteristics of faults in crystalline rocks change in fault zones during the ductile to brittle transitions.

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Ma, Svieda M., Dawn A. Kellett, Laurent Godin i Michael J. Jercinovic. "Localisation of the brittle Bathurst fault on pre-existing fabrics: a case for structural inheritance in the northeastern Slave craton, western Nunavut, Canada". Canadian Journal of Earth Sciences 57, nr 6 (czerwiec 2020): 725–46. http://dx.doi.org/10.1139/cjes-2019-0100.

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The north–northwest-striking Bathurst fault in the northeastern Slave craton displaced the 1.9 Ga Kilohigok basin and the ca. 2.02–1.96 Ga Thelon tectonic zone, and projects beneath the 1.7 Ga Thelon basin where unconformity-associated uranium deposits are spatially associated with basement faults. Here we investigate the deformation–temperature–time history of the Bathurst fault rocks using structural and microstructural observations paired with U–(Th–)Pb and 40Ar/39Ar geochronology. Highly strained hornblende-bearing granitoid rocks, the predominant rock type on the northeastern side of the Bathurst fault in the study area, show ambiguous sense of shear suggesting flattening by coaxial deformation. Quartz and feldspar microstructures suggest ductile deformation occurred at ≥500 °C. Along the main fault trace, brittle features and hydrothermal alteration overprint the pervasive ductile flattening fabric. In situ U–Th–Pb dating of synkinematic monazite suggests ductile fabric formation at ca. 1933 ± 4 Ma and ca. 1895 ± 11 Ma, and zircon from a cross-cutting dyke constrains the brittle deformation to ≤1839 ± 14 Ma. 40Ar/39Ar dating of fabric-defining minerals yield cooling ages of ca. 1920–1900 Ma and ca. 1900–1850 Ma for hornblende and muscovite, respectively, and a maximum cooling age of ca. 1840 Ma for biotite. We suggest the ca. 1933–1895 Ma ductile flattening fabric developed during orthogonal collision and indentation of the Slave craton into the Thelon tectonic zone and Rae craton. Brittle deformation on the Bathurst fault was localised parallel to the ductile flattening fabric after ca. 1840 Ma and preceded Thelon basin deposition. Brittle deformation features in Bathurst fault rocks preserve evidence for fluid–rock interaction and enhanced basement permeability, suggesting the fault is a possible conduit structure for mineralising fluids.

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Xing, Yan, Feng Gao, Zhizhen Zhang i Wenqi Zheng. "Energy Storage and Release of Class I and Class II Rocks". Energies 16, nr 14 (20.07.2023): 5516. http://dx.doi.org/10.3390/en16145516.

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As underground excavations become deeper, violent rock failures associated with the sudden release of elastic energy become more prevalent, threatening the safety of workers and construction equipment. It is important to figure out the energy-related failure mechanisms of rocks. However, the energy evolution across the complete deformation of different types of rocks and the effect of high confinement on energy storage and release are not well understood in the literature. In this study, a series of cyclic triaxial compression tests were conducted for Class I and Class II rocks to investigate the confinement-dependent characteristics of energy evolution. The results showed that three types of energy evolution were identified as the rock behavior changed from brittle to ductile. The energy storage limit was linearly enhanced by confinement. The nonlinear increase in dissipated energy at peak stress with increasing confinement was suggested to indicate the start of the brittle–ductile transition. The post-peak fracturing process was characterized using the ratio of the local withdrawn elastic energy and fracture energy, and a novel energy-based index was proposed to quantify the failure intensity of the rock. This paper presents a complete investigation of the energy conversion characteristics of the rock, which may shed light on the failure mechanisms of violent rock failures in underground projects.

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Tartarotti, Guerini, Rotondo, Festa, Balestro, Bebout, Cannaò, Epstein i Scambelluri. "Superposed Sedimentary and Tectonic Block-In-Matrix Fabrics in a Subducted Serpentinite Mélange (High-Pressure Zermatt Saas Ophiolite, Western Alps)". Geosciences 9, nr 8 (16.08.2019): 358. http://dx.doi.org/10.3390/geosciences9080358.

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The primary stratigraphic fabric of a chaotic rock unit in the Zermatt Saas ophiolite of the Western Alps was reworked by a polyphase Alpine tectonic deformation. Multiscalar structural criteria demonstrate that this unit was deformed by two ductile subduction-related phases followed by brittle-ductile then brittle deformation. Deformation partitioning operated at various scales, leaving relatively unstrained rock domains preserving internal texture, organization, and composition. During subduction, ductile deformation involved stretching, boudinage, and simultaneous folding of the primary stratigraphic succession. This deformation is particularly well-documented in alternating layers showing contrasting deformation style, such as carbonate-rich rocks and turbiditic serpentinite metasandstones. During collision and exhumation, deformation enhanced the boudinaged horizons and blocks, giving rise to spherical to lozenge-shaped blocks embedded in a carbonate-rich matrix. Structural criteria allow the recognition of two main domains within the chaotic rock unit, one attributable to original broken formations reflecting turbiditic sedimentation, the other ascribable to an original sedimentary mélange. The envisaged geodynamic setting for the formation of the protoliths is the Jurassic Ligurian-Piedmont ocean basin floored by mostly serpentinized peridotites, intensely tectonized by extensional faults that triggered mass transport processes and turbiditic sedimentation.

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Lu, Aihong, Xiya Chang, Shanchao Hu, Yu Xia i Ming Li. "Impact of Moisture Content on the Brittle-Ductile Transition and Microstructure of Sandstone under Dynamic Loading Conditions". Advances in Civil Engineering 2021 (4.05.2021): 1–16. http://dx.doi.org/10.1155/2021/6690171.

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Rockburst frequently occurred in an unstable or violent manner, which posed great safety risk and economic loss in deep underground engineering. The water injection into rock stratum was one of the most effectively ways to reduce rockburst by weakening rock mechanics. However, the moisture content was an important index related to rock mechanical properties. Many previous studies focused on the relationship between the moisture contents and macromechanical properties of rock materials under static load and seldom explored the impact of moisture variation on the mechanical properties and brittle-ductile transition characteristics of rock materials under dynamic loads. In this paper, we studied the dynamic mechanical properties of sandstone with different moisture contents under the same strain rate by the Split Hopkinson Pressure Bar (SHPB) experimental system. The relationship between dynamic mechanical properties of sandstone and moisture content was studied, and a dynamic ductility coefficient was proposed, which could be determined by the ratio between the peak strain and the yield strain. Then, it was used to assess the critical moisture content of the brittle-ductile transition of the sandstone. Through scanning electron microscopy (SEM) examination, the microstructure of sandstones with different moisture contents was inspected at magnifications of 500, 2000, and 5000 times, respectively. We showed that as the moisture content increased, the dynamic peak strength and elastic modulus decreased at different degrees, whereas the dynamic peak strain and ductility coefficient exhibited a nonlinear increase, respectively. When the moisture content reached 2.23%, the variation ratio of the dynamic ductility coefficient commenced to increase obviously, indicating that the sandstone began to transit from brittle behavior to ductile behavior. When the sample magnification was 500 times, the microstructure of the sandstone samples with zero and 2.01% to 2.40% moisture content mainly displayed the step pattern and river pattern, respectively, showing that the damage mode was brittle fracture. When the moisture content ranged from 2.49% to 2.58%, the microstructure of the sample included a large number of dimple clusters with local snake patterns and belonged to ductile fracture. When the sample magnification was 2000 and 5000 times, the microstructure was mainly brittle fracture with a moisture content lower than 2.23%. The microstructure of the sample with moisture content of 2.23% exhibited brittle-ductile composite fracture form, whereas others exhibited obviously ductile fracture. These characteristics were fundamentally consistent with the results reflected by the dynamic ductility coefficient. Our findings could provide a theoretical basis for mitigating coal and rock bursts by injecting water methods in underground coal mines.

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Koc, Salih, i Arash Dahi Taleghani. "A Fast Method to Determine the Critical Depth of Cut for Various Rock Types". Energies 13, nr 17 (31.08.2020): 4496. http://dx.doi.org/10.3390/en13174496.

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Knowing correct values of the rock mechanical properties is crucial for many engineering applications in subsurface. Rocks may show two failure modes during cutting: ductile and brittle. In the ductile mode, rock deforms plastically, and the debris is powdered ahead of the cutting face. On the other hand, chips are the major cutting characteristics for the brittle failure during rock cutting. The critical depth of cut represents the transition point between these two models, so knowing this value helps better predict the failure mechanism of rock. In this paper, a new method is introduced based on measuring the roughness of the groove for determining the transition point of failure modes for every rock sample after the scratch test. The graph depicting the average change in the surface roughness (Rt) versus the scratched surface roughness (ΔR) can be used to identify the rock failure mode and determine the transition point for the cutting process. The value of this slope increases until the depth of cut reaches the transition point, and then the slope reaches a constant value. The main purpose of this paper is to estimate the critical depth of cut of different rock specimens employing the new surface roughness model.

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Bai, Hao, Wei Du, Yundong Shou, Lichuan Chen i Filippo Berto. "Experimental investigation of cracking behaviors of ductile and brittle rock-like materials". Frattura ed Integrità Strutturale 15, nr 56 (28.03.2021): 16–45. http://dx.doi.org/10.3221/igf-esis.56.02.

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The cracking characteristics of ductile rocks were studied by similar materials with sand, barite, epoxide resin, polyamide, silicone rubber and alcohol, while the cracking characteristics of brittle rocks were investigated by similar material with sand, barite, rosin and alcohol. In this paper, to enhance the application range of the rock-like materials in the field of geotechnical engineering model tests, the values of the elastic modulus and the compressive strength of the artificial rock-like materials are changed in a wide range by adjusting the amount of cementitious materials (epoxide resin, polyamide, rosin, etc). The elastic modulus, compressive strength and cracking characteristics were obtained from the complete axial stress–strain curves of the specimens made of similar materials, which were cast using the different mixture ratios. These experimental data can provide quantitative investigation on mixture ratios of similar materials of rocks to model the geotechnical engineering. Furthermore, the effect of mixture ratios on mechanical properties and crack propagation pattern of specimens were also investigated by the specimens with pre-existing flaws under uniaxial compressive tests

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Rozprawy doktorskie na temat "Brittle and ductile rock"

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Ueda, Tadamasa. "Seismogenic deformation structures in the brittle-ductile transition regime: a case study of ultramafic pseudotachylytes and related deformed rocks in the Balmuccia peridotite body, Italy". 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/204571.

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Mahé, Stéphanie. "Etude de la fracturation et de la déformation d'un massif rocheux aux abords d'une faille d'échelle crustale dans le cadre du tracé du tunnel routier de Saint-Béat". Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20254/document.

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Le massif de marbres de Saint-Béat se situe dans la Zone Interne Métamorphique des Pyrénées centrales françaises. Il est formé de sédiments mésozoïques métamorphisés lors de l'événement métamorphique extensif Haute température - Basse pression classiquement décrit dans les Pyrénées. L'objet de cette thèse est de caractériser la déformation ductile et la fracturation qui affectent ce massif, et de déterminer dans quelle mesure les processus responsables de la fracturation peuvent être influencés par l'état de déformation. Les caractéristiques de la déformation des marbres et de ses roches encaissantes seront déterminées essentiellement grâce aux orientations préférentielles des axes de la calcite (marbre) et du quartz (socle paléozoïque), déterminées à l'aide de mesures à l'EBSD. L'observation en lame mince des textures de la calcite permet de quantifier les taux de déformation et d'estimer la température de cette déformation. Combinés aux observations de terrain, ces résultats permettent de proposer un modèle structural retraçant l'évolution du bassin depuis l'extension aptio-albienne jusqu'à son état actuel. La fracturation du massif est ensuite regardée à différentes échelles, depuis la photo aérienne jusqu'à l'affleurement. Quatre zones seront étudiées en détail afin de classifier les fractures par familles de mêmes caractéristiques et de reconstituer localement les paléo-régimes de contraintes. On comparera les tenseurs obtenus avec les régimes tectoniques décrits dans la littérature. Trois faciès légèrement différents de marbre servent de base à une étude visant à discuter de l'état d'anisotropie de la roche. Ainsi, des essais en compression simple, en traction indirecte et des mesures de vitesses acoustiques sont pratiqués sur des carottes orientées réalisées dans ces trois faciès ; leurs résultats donnent accès aux caractéristiques internes de la roche. On comparera et discutera les résultats d'un faciès à l'autre, et au sein du même faciès, d'une orientation à l'autre. Les résultats obtenus sur la fracturation servent de guide à la classification des fractures observées sur les fronts de tirs, lors du creusement du tunnel routier de Saint-Béat, recoupant le massif sur plus d'un kilomètre du Nord au Sud
The Saint-Béat massif, composed of different marble facies, is part of the Internal Metamorphic Zone of the French Central Pyrenees. It is formed by Mesozoic sediments metamorphosed by the High Temperature – Low Pressure extensional event, classically described in the Pyrenees. The aim of this work is to characterize the deformation and fractured state of the massif, and to understand how the former can constrain the latter. The ductile deformation state is recorded in calcite grains for Mesozoic rocks, or in quartz grains for Paleozoic rocks. Their preferential lattice orientations have been measured with the EBSD method. Calcite texture observations give indications about deformation rates and temperatures. These results, in addition with field observations, allow us to rebuild the structural evolution of the massif, from the Albian extension. Fracturing along the massif is described at different scales. Four outcrops are selected in order to characterize and to classify fractures, and locally reconstruct the paleo stress tensor. The obtained tensors are presented and compared to those already published. Three slightly different marble facies are used to discuss the degree of anisotropy of the rock. Mechanical experiments such as compression tests, tensile tests and velocity measurements of elastic waves are carried out on oriented cores within these three facies. These results provide internal rock characteristics which are discussed and compared for the three facies, and for different orientations of the cores

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Morgan, Robert Edward. "Ductile-brittle transitions in pipe grade polyethylene". Thesis, Imperial College London, 1994. http://hdl.handle.net/10044/1/7399.

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Bannister, Michael Keith. "Toughening of brittle materials by ductile inclusions". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292024.

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Samuels, J. "The brittle to ductile transition in silicon". Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382682.

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Venkatachalam, Sivaramakrishnan. "Predictive Modeling for Ductile Machining of Brittle Materials". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19774.

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Brittle materials such as silicon, germanium, glass and ceramics are widely used in semiconductor, optical, micro-electronics and various other fields. Traditionally, grinding, polishing and lapping have been employed to achieve high tolerance in surface texture of silicon wafers in semiconductor applications, lenses for optical instruments etc. The conventional machining processes such as single point turning and milling are not conducive to brittle materials as they produce discontinuous chips owing to brittle failure at the shear plane before any tangible plastic flow occurs. In order to improve surface finish on machined brittle materials, ductile regime machining is being extensively studied lately. The process of machining brittle materials where the material is removed by plastic flow, thus leaving a crack free surface is known as ductile-regime machining. Ductile machining of brittle materials can produce surfaces of very high quality comparable with processes such as polishing, lapping etc. The objective of this project is to develop a comprehensive predictive model for ductile machining of brittle materials. The model would predict the critical undeformed chip thickness required to achieve ductile-regime machining. The input to the model includes tool geometry, workpiece material properties and machining process parameters. The fact that the scale of ductile regime machining is very small leads to a number of factors assuming significance which would otherwise be neglected. The effects of tool edge radius, grain size, grain boundaries, crystal orientation etc. are studied so as to make better predictions of forces and hence the critical undeformed chip thickness. The model is validated using a series of experiments with varying materials and cutting conditions. This research would aid in predicting forces and undeformed chip thickness values for micro-machining brittle materials given their material properties and process conditions. The output could be used to machine brittle materials without fracture and hence preserve their surface texture quality. The need for resorting to experimental trial and error is greatly reduced as the critical parameter, namely undeformed chip thickness, is predicted using this approach. This can in turn pave way for brittle materials to be utilized in a variety of applications.

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Mohseni, Peyman. "Brittle and Ductile Fracture of X80 Arctic Steel". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19487.

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This PhD work has focused on the effect of microstructure and changes in microstructure introduced by welding procedure, on the brittle to ductile transition properties of high strength low alloy steels which have been developed for application at low temperatures (Arctic regions). For this purpose, the experimental work was based on the new pipeline steel API X80 that has a low transition temperature. The relationship between the brittle to ductile transition temperature and the microstructure in the coarse grained heat affected zone, CGHAZ, and the intercritically reheated coarse grained heat affected zone, ICCGHAZ was studied by applying Smitweld TCS1405 weld simulation for producing the HAZ microstructures. During the weld thermal cycles, both single and double cycle, the specimens were resistance heated to 1350°C by a rate of 150°C/s. The cooling rate was adjusted to give a cooling time between 800°C and 500°C (Δt8/5) of 15 seconds. The second heating cycle had a peak temperature, Tp2, of 780°C, and the cooling rate was the same as during the first cycle to simulate the reheated intercritical coarse grained HAZ. Fracture toughness was measured at low temperatures down to -90°C by both tensile and CTOD testing. In order to study the slip system activity of this steel, low cycle three point bending fatigue tests were also performed on polished specimens in the same temperature range. Fracture surfaces and changes in microstructure were analyzed by scanning and transmission electron microscopy and by light optical microscopy. In summary, the present work showed that, at each temperature the ICCGHAZ specimens had lower fracture toughness values than the CGHAZ specimens. Thus, the fracture mechanism is potentially more brittle in the case of ICCGHAZ specimens, and this is probably connected to the microstructure. The microstructure evalutions revealed that the ICCGHAZ contained blocky M-A constituents along prior austenite grain boundaries and stringer M-A constituents between the bainite laths. A more detailed investigation of the fracture surfaces by electron microscopy revealed also the existence of M-A constituents at the initiation points of the cleavage cracks. During deformation, the stress concentration is expected to increase due to the presence of the M-A constituents, and thus the level of stress and strain concentration around the M-A constituents become significantly larger than the nominal stress value and then causes initiation of cleavage fracture. Fracture surface analysis of fractured specimens documented that the cracks initiated either from debonded M-A constituents or from the region between two or more closely separated blocky M-A constituents where the transformation induced stress fields overlapped. In the present work, the initiation of cleavage fracture occurred within the double CTOD distance from the crack tip. This implies that brittle fracture is easily initiated when M-A constituents are located near the fatigue crack tip, and it is also controlled by accumulation of continuum stress fields and local plastic strains. The slip system analysis revealed that several slip systems are activated with a variety of Schmid factors within one grain, and in some cases the first activated slip system is not necessarily that with the highest Schmid factor. Thus, it can be concluded that the Schmid factor is not the only parameter that determines activation of slip. Finally, the crystallographic facet analysis by EBSD illustrated that the {100} planes are the most potent cleavage facet planes in both CGHAZ and ICCGHAZ specimens. It was also shown that the {100} and {110} planes in the case of CGHAZ, and the {100} and {211} planes in the case of ICCGHAZ were the most favourable cleavage facet planes at subzero temperatures.

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Serbena, F. C. "The brittle-ductile transition of NiAl single crystals". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294341.

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Ellis, M. "The ductile to brittle transition in BCC metals". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306220.

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Jeng, Fu Shu. "Deep penetration into frictional ductile and brittle materials". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13096.

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Książki na temat "Brittle and ductile rock"

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G, Duba A., i Heard H. C. 1931-, red. The Brittle-ductile transition in rocks: The Heard volume. Washington, D.C: American Geophysical Union, 1990.

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Duba, A. G., W. B. Durham, J. W. Handin i H. F. Wang, red. The Brittle‐Ductile Transition in Rocks. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056.

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Liu, Kui, Hao Wang i Xinquan Zhang. Ductile Mode Cutting of Brittle Materials. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-32-9836-1.

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Horii, H. Brittle failure in compression: Splitting, faulting and brittle-ductile transition. London: The Royal Society, 1986.

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L, Blumberg Selinger Robin, red. Fracture: Instability dynamics, scaling, and ductile/brittle behavior. Pittsburgh, Pa: Materials Research Society, 1996.

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Zhang, Yun-Quan. The ductile-to-brittle transition in ferritic steels. Birmingham: University of Birmingham, 1995.

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Joyce, J. A. Ductile to brittle toughness transition characterization of A533B steel. Washington, DC: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1988.

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R, Desmorat, red. Engineering damage mechanics: Ductile, creep, fatigue and brittle failures. Berlin: Springer, 2005.

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Joyce, J. A. Ductile to brittle toughness transition characterization of A533B steel. Washington, DC: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1988.

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Zia-Ebrahimi, F. Ductile-to-brittle transition in steel weldments for arctic structures. Boulder, Colo: U.S. Dept. of Commerce, National Bureau of Standards, 1985.

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Więcej źródeł

Części książek na temat "Brittle and ductile rock"

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Paterson, M. S. "Rock deformation experimentation". W The Brittle‐Ductile Transition in Rocks, 187–94. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0187.

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Evans, Brian, Joanne T. Fredrich i Teng-fong Wong. "The brittle-ductile transition in rocks: Recent experimental and theoretical progress". W The Brittle‐Ductile Transition in Rocks, 1–20. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0001.

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Kronenberg, Andreas K., Paul Segall i George H. Wolf. "Hydrolytic weakening and penetrative deformation within a natural shear zone". W The Brittle‐Ductile Transition in Rocks, 21–36. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0021.

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Carlson, S. R., M. Wu i H. F. Wang. "Micromechanical modeling of thermal cracking in granite". W The Brittle‐Ductile Transition in Rocks, 37–48. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0037.

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Chester, F. M., i J. M. Logan. "Frictional faulting in polycrystalline halite: Correlation of microstructure, mechanisms of slip, and constitutive behavior". W The Brittle‐Ductile Transition in Rocks, 49–65. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0049.

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Tullis, Jan, Lisa Dell'Angelo i Richard A. Yund. "Ductile shear zones from brittle precursors in feldspathic rocks: The role of dynamic recrystallization". W The Brittle‐Ductile Transition in Rocks, 67–81. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0067.

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Chokshi, Atul H., i Amiya K. Mukherjee. "The role of hydrostatic pressure in the cavitation failure of a superplastic aluminum-lithium alloy". W The Brittle‐Ductile Transition in Rocks, 83–89. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0083.

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Bernabe, Yves, i W. F. Brace. "Deformation and fracture of Berea sandstone". W The Brittle‐Ductile Transition in Rocks, 91–101. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0091.

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Horseman, S. T., i J. Handin. "Triaxial-compression tests on rocksalt at temperatures from 50° to 200°c and strain rates from 10−4 to 10−9/s". W The Brittle‐Ductile Transition in Rocks, 103–10. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0103.

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Russell, J. E., N. L. Carter i S. C. Walker. "A Material model for Avery Island rocksalt". W The Brittle‐Ductile Transition in Rocks, 111–18. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm056p0111.

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Streszczenia konferencji na temat "Brittle and ductile rock"

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Miedema, Sape A. "A New Approach to Determine Cutting Forces in Brittle Rock Under Hyperbaric Conditions". W ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23435.

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Merchant (1944), (1945A) and (1945B) derived a model for determining the cutting forces when machining steel. The model was based on elastic-plastic deformation and a continuous chip formation (ductile cutting). The model included internal and external friction and shear strength, but no adhesion, gravity, inertia and pore pressures. Later Miedema (1987 September) extended this model with adhesion, gravity, inertial forces and pore water pressures. These models however only describe the so called Flow Type of cutting process, which is the ductile cutting process. The ductile cutting process requires a relatively large tensile strength (BTS) compared to the compressive strength (UCS) or shear strength. If the tensile strength is not large enough, brittle failure based on tensile failure may occur. This paper describes a new method of determining the cutting forces resulting from brittle failure, still based on the original ductile models, but with a correction for the stresses. This new model can be used for Deep Sea Mining Applications. It is assumed that materials which behave brittle under atmospheric conditions will behave ductile under hyperbaric conditions.

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Logan, John M. "Porosity and the brittle-ductile transition in sedimentary rocks". W AIP Conference Proceedings Vol. 154. AIP, 1987. http://dx.doi.org/10.1063/1.36397.

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Khan, Mohammad Rasheed, Guenther Glatz, Devon Chikonga Gwaba i Gallyam Aidagulov. "A Novel Methodology to Investigate Critical Depth for Ductile-to-Brittle Transition During Scratch Testing". W Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207409-ms.

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Abstract More than two decades have passed since the introduction of the scratch testing method for rock strength determination. The test method typically involves dragging a rigid-shaped cutter across the rock surface at a fixed cutting depth. This depth determines the failure mechanism of the rock, ductile for shallow depths and brittle for deeper. In the ductile mode, intrinsic specific energy is primarily a measure of the unconfined-compressive-strength (UCS), which is pivotal for rate of penetration (ROP) during drilling and for borehole stability analysis. On the contrary, brittle failure can lead to permanent core damage and is usually not desired as it impacts interpretation of the scratch testing results. Consequently, it is imperative to identify the critical depth, and at which transition from ductile to brittle failure occurs which will help optimize rock testing and tool designs. In this study, a novel methodology is proposed utilizing micro-computed tomography (CT) imaging to determine critical depth through morphological analysis of scratch test cuttings. Scratch tests are carried out on Indiana limestone core samples with the cutter-rock interaction geometry characterized by a cutter width of 10mm and a back-rake angle of 15°. The sample is scratched in the range of 0.05mm to 0.40mm with increments of 0.05mm. Scratch powder is carefully collected after each scratch increment and stored for further analysis. This powder is then loaded into slim rubber tubes and imaged at a high resolution of 1 µm with a helical micro-CT scanner. The scans are then reconstructed using a computer program to initiate the visualization of individual grains from each cutter depth including evaluation of grain morphologies. Finally, the results from this morphological analysis are corroborated and compared with three other methods: force response analysis, force inflection point analysis, and the size effect law (SEL). Based on shape analysis, it was found that the transition from ductile to brittle regime occurs at a depth of 0.25mm. Elongation and appearance of the enhanced degree of angularity of the grains as the depth of cut (DOC) increases past 0.25mm was observed. Moreover, large grain sizes were detected and are representative of formation of chips (typical brittle regime response). Furthermore, it is illustrated that the image analysis helps eliminate the ambiguity of force signal analysis and in combination can aid in the critical depth of cut determination. The other methods involving force alone and the SEL are not able to pin-point onset of brittle regime. Using a similar methodology, creation of a database for various rock types is recommended to develop a guide for the depth of cut selection during scratch testing. This novel methodology utilizing micro-CT analysis and comparative study with other techniques will put in place an accurate strategy to determine the critical depth of cut when designing rock scratch testing programs.

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Miedema, Sape A., i Djurre Zijsling. "Hyperbaric Rock Cutting". W ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83249.

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Under atmospheric conditions rock cutting is mostly brittle; either based on tensile cracks or based on shear cracks, although ductile cutting is possible. It is known from the drilling industry that under very high hydrostatic pressures often a sort of ductile cutting process occurs. Cutting under very high hydrostatic pressures is called hyperbaric cutting. Combining the cutting theory of water saturated sand of Miedema and the classic rock cutting theory of Merchant, the 2M theory, results in a new application of the theory for hyperbaric rock cutting. The new theory contains the pore pressure and the cohesive terms. To verify this theory the measurements of Zijsling (1987) are used, which go up to pressures of 1000 bar. A complication is that the chips cut will start to curl, but the contact length of the chip cut with the blade is unknown. Using the equilibrium of moment’s, results in a method for determining this contact length. In the specific case a contact length of about 4–5 times the layer thickness is found, resulting in an almost perfect match with the measurements. The paper shows the measurements and the theory.

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Tran, Thi-Phuong-Huyen, Sy-Hung Nguyen i Stephane Bouissou. "Experimental Study of the Strain Localization in a Rock Analogue Material at Brittle-Ductile Transition". W 2020 5th International Conference on Green Technology and Sustainable Development (GTSD). IEEE, 2020. http://dx.doi.org/10.1109/gtsd50082.2020.9303057.

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Bakir, Barkin, Hossein Mohammadi i John A. Patten. "Ductile Regime Scratching of a Rock Sample in a Laser Assisted Machining Technique". W ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-2758.

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Rocks are playing an important role in the life of mankind since ancient times. One of the most significant characteristics of the rocks is their brittleness, which makes them exhibit a very poor machinability and usually severe fracture results during machining. In this paper, Micro-Laser Augmented Machining (μ-LAM) technique is applied on scratching a commercial rock, Gabbro-Labradorite, which is a composite of grained natural minerals such as feldspar, magnetite and mica. In the μ-LAM process, a laser is used to locally heat and thermally soften the materials below the scratching tool during the machining operation. In this paper, scratching tests have been done on the Gabbro-Labradorite minerals, with and without laser heating and results are compared and reported. Micro-laser assisted scratch tests (with an actual cutting tool) were successful in demonstrating the enhanced thermal softening of the feldspar and magnetite minerals. The effect of the laser power was studied by measuring the depths of the cuts for the scratch tests. When generating the scratches with a diamond tool, load range was increased from 50 to 500 mN. Laser powers of 10, 15, 20, and 25 Watt (W) have been utilized. All the tests were repeated two times to increase the reliability of the results. 3D profiles were generated by using a white light interferometer and microscopic images of the cuts have been reported. Results show that Ductile to Brittle Transition (DBT) depth, which is the critical depth for machining brittle materials, increased with the aid of the laser. Results are very important for the machining of the Gabbro-Labradorite to get a high material removal rate (MRR), low tool wear and better surface quality.

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Yasin, Qamar, Du Qizhen, Atif Ismail i GMD Sohail. "Effects of Pore Pressure and Organic Contents on the Brittle-Ductile Transition in Shale Rock Using Geophysical Method". W Unconventional Resources Technology Conference. Tulsa, OK, USA: American Association of Petroleum Geologists, 2016. http://dx.doi.org/10.15530/urtec-2016-2423081.

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Rozanov, A., D. Petrov, A. Gladyr i P. Korchak. "Acoustic Emission Analysis of Brittle and Ductile Behavior of Rocks at Critical Stresses". W 82nd EAGE Annual Conference & Exhibition. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202011927.

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Ferrie, Nicole, Cailey Condit, Melodie French i Jason Ott. "CONSTRAINING DEFORMATION PROCESSES IN THE BRITTLE-DUCTILE TRANSITION REGION BELOW A SUBDUCTION SEISMOGENIC ZONE". W Joint 118th Annual Cordilleran/72nd Annual Rocky Mountain Section Meeting - 2022. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022cd-374149.

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Hagengruber, Tyler L. "Strength effects of microfracture on granular microstructures evaluated by FDEM direct numerical simulation". W 56TH US ROCK MECHANICS / GEOMECHANICS SYMPOSIUM. OnePetro, 2022. http://dx.doi.org/10.56952/arma-2022-2209.

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We present results of an investigation into the mechanisms of damage in granular microstructures conducted through direct numerical simulation with the combined Finite-Discrete Element Method (FDEM). Scanning Electron Microscope (SEM) images of a pressed crystalline powder are directly meshed, resolving grain-grain interfaces. Semi-ductile microfracture is simulated by prescribing a combination of inter-granular brittle fracture and intra-granular grain plasticity. Pristine (undamaged) and damaged microstructures are simulated in uniaxial compression tests and compared to experimental uniaxial compression measurements from literature. The simulation results show that the observed microscale mechanisms of damage (microfracture predominantly around and sometimes through grains and crack associated pore-growth) can well explain degradation of strength observed in the laboratory measurements. A method of tracing grain boundaries from SEM images is described and applied to meshing of a microstructure damaged through cyclic thermal loading. By calibrating the simulations to the damaged and undamaged experimental measurements, micro-mechanical/structural insight is gained into the mechanisms of damage for the material. The results show that the SEM-based micro-characterization of damage can explain the degradation in effective strength observed in the testing and can be accurately modeled using the presented methods.

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Raporty organizacyjne na temat "Brittle and ductile rock"

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Argon, A. S., i Q. Berg. Brittle to ductile transition in cleavage fracture. Office of Scientific and Technical Information (OSTI), wrzesień 1992. http://dx.doi.org/10.2172/6976893.

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Argon, A. Brittle to ductile transition in cleavage fracture. Office of Scientific and Technical Information (OSTI), styczeń 1989. http://dx.doi.org/10.2172/5450739.

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Luh, M. H., i J. S. Strenkowski. Simulations of ductile flow in brittle material processing. Office of Scientific and Technical Information (OSTI), grudzień 1988. http://dx.doi.org/10.2172/476646.

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Schulson, Erland M. The Ductile to Brittle Transition in Polycrystalline Ice under Compression. Fort Belvoir, VA: Defense Technical Information Center, sierpień 1993. http://dx.doi.org/10.21236/ada271182.

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Zia-Ebrahimi, F. Ductile-to-brittle transition in steel weldments for arctic structures. Gaithersburg, MD: National Bureau of Standards, 1985. http://dx.doi.org/10.6028/nbs.ir.85-3020.

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Carr, S. D. Ductile shearing and brittle faulting in Valhalla gneiss complex, southeastern British Columbia. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1985. http://dx.doi.org/10.4095/120029.

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Link, R. E., i J. A. Joyce. Application of fracture toughness scaling models to the ductile-to- brittle transition. Office of Scientific and Technical Information (OSTI), styczeń 1996. http://dx.doi.org/10.2172/191633.

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Klueh, R. L., i D. J. Alexander. Neutron irradiation effects on the ductile-brittle transition of ferritic/martensitic steels. Office of Scientific and Technical Information (OSTI), sierpień 1997. http://dx.doi.org/10.2172/543208.

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Wiersma, B. J. Measurement of the ductile to brittle transition temperature for waste tank cooling coils. Office of Scientific and Technical Information (OSTI), wrzesień 1992. http://dx.doi.org/10.2172/10138772.

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Wiersma, B. J. Measurement of the ductile to brittle transition temperature for waste tank cooling coils. Office of Scientific and Technical Information (OSTI), wrzesień 1992. http://dx.doi.org/10.2172/6893714.

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