The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Liu Haizhang - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Transformation and Low-Temperature Deformation of Ti-51.1Ni Shape Memory Alloy
Rare Metal Materials and Engineering, 2017Co-Authors: Bi Zongyue, Wang Jingli, Liu HaizhangAbstract:Abstract Effects of annealing temperature on the phase transformation and the low temperature Deformation characteristics in the deformed Ti-51.1Ni (at%) shape memory alloy (SMA) were investigated by differential scanning calorimetry (DSC), optical microscope (OM) and tensile test. The results show that the transformation types of Ti-51.1Ni alloy are changing from A→R/M→R→A to A→R→M/M→R→A to A→R→M/M→A (A-parent phase B2, R-R phase, M-martensite phase) upon cooling/heating along with increasing annealing temperature. The R transformation temperatures and martensite temperature hysteresis decrease, while the M transformation temperature increases and the R temperature hysteresis nearly keeps at about 6.5 °C. When Deformation happen at 10 °C, the 400∼550 °C annealed Ti-51.1Ni SMA exhibits as the shape memory effect (SME) + superelasticity (SE), the 600∼700 °C annealed SMA shows SE, and the characteristics of alloy change from SME + SE to SE. In addition, the annealing recrystallization temperature of Ti-51.1Ni SMA is 590 °C, and the 590∼650 °C annealed alloy could obtain excellent capability of plastic Deformation and 50.83 % values of fracture strain, so the forming processing temperature could be in the range of 590∼650 °C. When the Ti-51.1Ni alloy are used for energy consumption of damper and damping device, the suitable annealing temperature could be higher than 550 °C, and for making superelastic device, the suitable annealing temperature could be below 400 °C or above 600 °C.
I. V. Makovetskii - One of the best experts on this subject based on the ideXlab platform.
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Low-Temperature Deformation and strength of alloy steels under complex stress conditions
Strength of Materials, 2010Co-Authors: A. A. Lebedev, V. P. Lamashevskii, I. V. MakovetskiiAbstract:We present experimental data on the Low-Temperature Deformation behavior of some alloy structural steels under plane stress conditions simulating the material operation in pipe and shell structures. The experimental part of the investigations involves loading of thin-walled shell specimens with an axial force (tension, compression) and internal pressure, including tests at low temperatures.
Tresa M. Pollock - One of the best experts on this subject based on the ideXlab platform.
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A comparative analysis of low temperature Deformation in B2 aluminides
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: Tresa M. Pollock, D.c. LuAbstract:Abstract The microscopic and macroscopic Deformation characteristics of three different classes of B2 aluminides have been studied: FeAl, NiAl and RuAl. Strain rate change experiments over the temperature range of −196 to 600°C reveal a high temperature sensitivity of the flow stress, high rate sensitivity and low activation areas for Deformation in NiAl, in contrast to FeAl and RuAl. NiAl, like many other higher temperature B2 compounds, deforms by glide of 〈100〉 dislocations. The 〈100〉 dislocations are subject to frequent cross slip that constrains Deformation and results in the formation of a high density of jogs and dipoles. Fe–40Al–0.2Zr, similar to other lower temperature B2 compounds, deforms by glide of relatively mobile 〈111〉 dislocations. RuAl displays unusual Deformation characteristics for a compound with a high melting point of 2060°C. Following Deformation, approximately equal densities of 〈100〉 and 〈110〉 dislocations are present on {110} planes over the range of temperatue investigated. The implications of these observations with respect to the ‘intrinsic deformability’ of B2 aluminides is discussed.
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Low temperature Deformation and dislocation substructure of ruthenium aluminide polycrystals
Acta Materialia, 1999Co-Authors: D.c. Lu, Tresa M. PollockAbstract:Abstract The flow behavior and dislocation substructure present in ruthenium aluminide polycrystals due to Deformation at room temperature and 77 K have been studied. Dislocations with three different types of Burgers vectors have been identified after 1–2% Deformation in compression at 77 K and room temperature: 〈100〉, 〈110〉 and 〈111〉. The 〈100〉 and 〈110〉 dislocations are present with approximately equal densities, while the 〈111〉 are only occasionally observed. Trace analyses show that the majority of the dislocations are mixed in character and lie on {110} type planes. The implications of these observations with regard to the number of independent slip systems and the intrinsic deformability of this material are discussed.
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Low temperature Deformation kinetics of ruthenium aluminide alloys
MRS Proceedings, 1998Co-Authors: D.c. Lu, Tresa M. PollockAbstract:The kinetics of low temperature Deformation were investigated in several different polycrystalline RuAl alloys with the use of strain rate change experiments at 77 K and 298 K. Compositions investigated include RuAl, RuAl+0.5%B, Ru{sub 51.5}Al{sub 48.5}, Ru{sub 52}Al{sub 48}, Ru{sub 53}Al{sub 47}+0.5%B. Ru{sub 54.5}Al{sub 45.5}, and Ru{sub 52}Al{sub 43}Sc{sub 5}. Flow stresses did not vary substantially with temperature between 77 K and 298 K. Rate sensitivities were low compared to other B2 compounds and similar in all compositions investigated. Analyses of dislocation substructures after low strain Deformation were conducted. The Deformation kinetics and substructural observations suggest a higher intrinsic deformability for RuAl alloys with respect to the other high temperature B2 aluminides.
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Rate sensitivities for low temperature Deformation in ruthenium aluminide alloys
Scripta Materialia, 1998Co-Authors: D. Lu, Tresa M. PollockAbstract:Because of the need for new high temperature structural materials, a number of binary and multicomponent B2 aluminides have been investigated in recent years. Some alloys based on FeAl and Nb-Ti-Al are relatively ductile at low temperatures, but suffer from environmental embrittlement and/or relatively low melting temperatures. One apparent exception to the brittle behavior of the higher temperature B2 aluminides is ruthenium aluminide, RuAl, which has a melting point of approximately 2,060 C. Fleischer et al. have reported a high room temperature toughness and high compressive ductilities for a number of alloys based on RuAl, compared to a variety of other intermetallic compounds. The objective of the experiments reported here was to measure room temperature rate sensitivities for a number of the same RuAl-based alloys, to determine if the phenomenological flow parameters that relate to dislocation glide processes are also unusual, compared to other higher temperature B2 compounds.
V. P. Pilyugin - One of the best experts on this subject based on the ideXlab platform.
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Differing behaviors of point defects in Fe–36Ni alloy during annealing after Low-Temperature Deformation and irradiation
Technical Physics Letters, 2017Co-Authors: V. V. Sagaradze, N. V. Kataeva, V. P. Pilyugin, V. L. Arbuzov, S. E. Danilov, V. A. Shabashov, A. V. LitvinovAbstract:Fe–36Ni alloy is studied in states in which it is quenched, irradiated with electrons at 70 K, and deformed at 77 K. It is shown that similar structure-phase transformations occur in the investigated alloy during annealing at the temperature range of 70–570 K both after preliminary Low-Temperature electron irradiation and after preliminary Low-Temperature Deformation. Migration of interstitial atoms (70–140 K) and vacancies (180–570 K), which induce phase transformations and are the results of atomic separation and ordering of zones with increased nickel content, is observed. Mechanisms of structure-phase changes under Deformation and annealing are discussed.
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Structure evolution of pure iron upon Low-Temperature Deformation under high pressure
Physics of Metals and Metallography, 2010Co-Authors: V. P. Pilyugin, L. M. Voronova, M. V. Degtyarev, T. I. Chashchukhina, V. B. Vykhodets, T. E. KurennykhAbstract:Structure evolution of iron (99.97% purity) deformed by shear under pressure at 80 K in a medium of liquid nitrogen has been investigated. It has been found that, along with dislocation slip, twinning and development of Deformation microbands become operative mechanisms of Low-Temperature Deformation. This led to specific type of inhomogeneity of the structure in which, up to ultimately attained degrees of Deformation, low-angle misorientations are retained and, unlike room-temperature Deformation, no homogeneous submicrocrystalline (SMC) structure is formed. Twinning contributes to the refinement of structure elements that are more than 1 μm in size; the further refinement occurs by the dislocation-disclination mechanism and goes to the steady-state stage.
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Evolution of the structure and hardness of nickel upon cold and Low-Temperature Deformation under pressure
Physics of Metals and Metallography, 2008Co-Authors: V. P. Pilyugin, L. M. Voronova, T. I. Chashchukhina, T. M. Gapontseva, L. I. Shchinova, M. V. DegtyarevAbstract:The effect of the Deformation temperature ensuring different mobility of dislocations on the change of stages of the structural state of single-crystal nickel has been studied. It has been shown that the Deformation temperature affects the type of arising boundaries and the degree of Deformation that corresponds to the transition of the material to a new structural state. The formation of microtwins and Deformation bands in the structure at the liquid-nitrogen temperature not only retards the formation of a homogeneous submicrocrystalline structure but also leads to a lesser strain hardening.
Didier Marquer - One of the best experts on this subject based on the ideXlab platform.
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Dating Low-Temperature Deformation by 40Ar/39Ar on white mica, insights from the Argentera-Mercantour Massif (SW Alps)
Lithos, 2020Co-Authors: Guillaume Sanchez, Yann Rolland, Julie Schneider, Michel Corsini, Emilien Oliot, Philippe Goncalves, Chrystèle Verati, Jean-marc Lardeaux, Didier MarquerAbstract:International audienceIn order to date Low-Temperature Deformation, intensely trained muscovite porphyroclasts and neocrystallized shear band phengite from greenschist-facies shear zones have been dated by 40Ar/39Ar method in the Argentera-Mercantour massif. Shear zones are featured by gradual mylonitization of a Variscan granite, gneiss and Permian pelite protolith (300-315Ma) during the Alpine orogenic event. Mineralogical and textural observations indicate that phengites and chlorites developed from biotite and plagioclase in fluid system during Deformation following dissolution-transport-precipitation reactions of the type biotite + plagioclase + aqueous fluid = chlorite + albite + phengite + quartz + titanite + K-bearing fluid in the granite-gneiss mylonite. Contrariwise, phengite developed at the expense of clays following substitution reaction in pelite mylonite. Based on conventional thermobarometry on phengite and chlorite and Pressure-Temperature-aqueous fluid (P-T-MH2O) pseudosections calculated with shear zone bulk compositions, the conditions during shear Deformation were estimated at 375±30 °C and 4.8-7±1 kbar in an H2O-satured system. In this low temperature environment, 40Ar/39Ar analysis of the Variscan muscovite for various grades of ductile strain intensity shows a limited 40Ar/39Ar isotopic resetting, all ages scattering between 296 and 315 Ma. Under conditions of intense ductile Deformation and large scale fluid circulation, muscovite grains formed during the Variscan retain their much older ages. 40Ar/39Ar dating of very fine grained synkinematic phengite grains, neoformed during the Alpine history, give consistent plateau ages (34-20 Ma) for each shear zone. In detail, 40Ar excess can be detected in the pelite mylonitic sample where phengites crystallized by substitution process while the other mylonitic samples where phengites grow from fluid-induced reactions do not evidence any 40Ar excess. These results demonstrate that the 40Ar/39Ar dating of neocrystallized synkinematic white mica allows the determination of precise ages of Deformation and fluid activity. Together with precise thermobarometry undertaken on the basis of mineral chemistry and whole-rock composition, 40Ar/39Ar dating of white mica leads to the reconstitution of precise depth-Deformation history of low-grade (b400 °C) metamorphic units. At the Argentera-Mercantour massif scale, several stages of shear zone development at 15-21 km depth are dated between 33 and 20Ma. In the SE part of the massif shear zone ages are well constrained to be either (1) 33.6±0.6 Maor in the range (2) 26.8±0.7Ma-26.3±0.7 Ma. In the West of the massif, younger shear zone ages range between (3) 22.2±0.3 Ma and (4) 20.5±0.3 Ma
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Dating Low-Temperature Deformation by 40Ar/39Ar on white mica, insights from the Argentera-Mercantour Massif (SW Alps)
Lithos, 2011Co-Authors: Guillaume Sanchez, Yann Rolland, Julie Schneider, Michel Corsini, Emilien Oliot, Philippe Goncalves, Chrystèle Verati, Jean-marc Lardeaux, Didier MarquerAbstract:In order to date Low-Temperature Deformation, intensely strained muscovite porphyroclasts and neocrystallized shear band phengite from greenschist-facies shear zones have been dated by 40Ar/39Ar method in the Argentera-Mercantour massif. Shear zones are featured by gradual mylonitization of a Variscan granite, gneiss and Permian pelite protolith (300–315 Ma) during the Alpine orogenic event. Mineralogical and textural observations indicate that phengites and chlorites developed from biotite and plagioclase in fluid system during Deformation following dissolution–transport–precipitation reactions of the type biotite + plagioclase + aqueous fluid = chlorite + albite + phengite + quartz + titanite + K-bearing fluid in the granite-gneiss mylonite. Contrariwise, phengite developed at the expense of clays following substitution reaction in pelite mylonite. Based on conventional thermobarometry on phengite and chlorite and Pressure–Temperature-aqueous fluid (P–T-MH2O) pseudosections calculated with shear zone bulk compositions, the conditions during shear Deformation were estimated at 375 ± 30 °C and 4.8–7 ± 1 kbar in an H2O-satured system. In this low temperature environment, 40Ar/39Ar analysis of the Variscan muscovite for various grades of ductile strain intensity shows a limited 40Ar/39Ar isotopic resetting, all ages scattering between 296 and 315 Ma. Under conditions of intense ductile Deformation and large-scale fluid circulation, muscovite grains formed during the Variscan retain their much older ages. 40Ar/39Ar dating of very fine grained synkinematic phengite grains, neoformed during the Alpine history, give consistent plateau ages (34–20 Ma) for each shear zone. In detail, 40Ar excess can be detected in the pelite mylonitic sample where phengites crystallized by substitution process while the other mylonitic samples where phengites grow from fluid-induced reactions do not evidence any 40Ar excess. These results demonstrate that the 40Ar/39Ar dating of neocrystallized synkinematic white mica allows the determination of precise ages of Deformation and fluid activity. Together with precise thermobarometry undertaken on the basis of mineral chemistry and whole-rock composition, 40Ar/39Ar dating of white mica leads to the reconstitution of precise depth-Deformation history of low-grade (
