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Liang Zhen - One of the best experts on this subject based on the ideXlab platform.
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Deformed Microstructure evolution in am60b mg alloy under hypervelocity impact at a velocity of 5 km s 1
Materials & Design, 2010Co-Authors: Dong-li Zou, Liang Zhen, Y.d. Zhu, W.z. Shao, B.j. PangAbstract:Abstract Deformed Microstructure in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s −1 were investigated through optical microscope, scanning electron microscope and transmission electron microscope. The results show that four Deformed zones around the crater can be classified based on the different Deformed Microstructure, including ultrafine grain zone, ultrafine grain and deformation twin zone, high and low density deformation twin zones. The dislocation slipping, deformation twins and ultrafine grains are the dominant components in the four Deformed zones, and the evolution of Deformed Microstructure is speculated based on the Deformed Microstructure observed in four zones. Slipping and twinning play a critical role for the formation of the dynamic recrystallized grains, and twinning-induced rotational dynamic recrystallization mechanism is thought to be the main mechanism for the formation of ultrafine grains. The microhardness and dynamic compressive strength in different Deformed zones were measured, and the high microhardness and yield strength in ultrafine grain zone should be attributed to the strain hardening and grain refining.
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Deformed Microstructure and mechanical properties of am60b magnesium alloy under hypervelocity impact at a velocity of 4 km s 1
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Liang Zhen, Chengyan Xu, Wenzhu Shao, B.j. PangAbstract:Abstract Deformed Microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s −1 were studied through optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and indenter technique. The results show that the Deformed Microstructure below the crater can be classified as three zones, i.e. dynamic recrystallization zone, high density deformation twin zone and low density deformation twin zone. The refined and equiaxed recrystallized grains adjacent to the crater were formed, which should be attributed to the twining-induced dynamic recrystallization mechanism. The { 1 0 1 ¯ 2 } , { 1 0 1 ¯ 1 } deformation twins are confirmed through selected area electron diffraction (SAED) technique. The microhardness and yield strength in the Deformed Microstructure zone near the crater are much higher than that of the matrix, which should be attributed to strain hardening and grain refining.
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Deformed Microstructure evolution in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s−1
Materials & Design, 2010Co-Authors: Dong-li Zou, Liang Zhen, Y.d. Zhu, W.z. Shao, B.j. PangAbstract:Abstract Deformed Microstructure in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s −1 were investigated through optical microscope, scanning electron microscope and transmission electron microscope. The results show that four Deformed zones around the crater can be classified based on the different Deformed Microstructure, including ultrafine grain zone, ultrafine grain and deformation twin zone, high and low density deformation twin zones. The dislocation slipping, deformation twins and ultrafine grains are the dominant components in the four Deformed zones, and the evolution of Deformed Microstructure is speculated based on the Deformed Microstructure observed in four zones. Slipping and twinning play a critical role for the formation of the dynamic recrystallized grains, and twinning-induced rotational dynamic recrystallization mechanism is thought to be the main mechanism for the formation of ultrafine grains. The microhardness and dynamic compressive strength in different Deformed zones were measured, and the high microhardness and yield strength in ultrafine grain zone should be attributed to the strain hardening and grain refining.
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Characterization of the Deformed Microstructure in 1Cr18NiTi stainless steel under ballistic impact
Materials Science and Engineering: A, 2008Co-Authors: Liang Zhen, D.l. Zou, Wenzhu ShaoAbstract:Abstract Microstructural characteristics of 1Cr18Ni9Ti stainless steel impacted by GCr15 projectiles at a velocity of 2–6 km/s was studied through the optical microscope, SEM, TEM and EBSD techniques. The experimental results show that the adiabatic shear bands beneath the crater are observed, and its width is ranging from 1 to 10 μm. The deformation twins, martensite and intersection between them are observed simultaneously under the crater, which should be attributed to the high strain rate impact. The elongated subgrains with high aspect ratio are found in the shear band, while the melt-related Microstructure is observed in the shear band. The heat converted from plastic work continuously increases the local temperature and thus leads to continued softening, even melting, in the material. According to the constitutive equation, the temperature calculated inside a shear band can be rose to the melting point of the material, which explains the melt-related Microstructure observed inside shear bands simply.
Wenzhu Shao - One of the best experts on this subject based on the ideXlab platform.
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Deformed Microstructure and mechanical properties of am60b magnesium alloy under hypervelocity impact at a velocity of 4 km s 1
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Liang Zhen, Chengyan Xu, Wenzhu Shao, B.j. PangAbstract:Abstract Deformed Microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s −1 were studied through optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and indenter technique. The results show that the Deformed Microstructure below the crater can be classified as three zones, i.e. dynamic recrystallization zone, high density deformation twin zone and low density deformation twin zone. The refined and equiaxed recrystallized grains adjacent to the crater were formed, which should be attributed to the twining-induced dynamic recrystallization mechanism. The { 1 0 1 ¯ 2 } , { 1 0 1 ¯ 1 } deformation twins are confirmed through selected area electron diffraction (SAED) technique. The microhardness and yield strength in the Deformed Microstructure zone near the crater are much higher than that of the matrix, which should be attributed to strain hardening and grain refining.
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Characterization of the Deformed Microstructure in 1Cr18NiTi stainless steel under ballistic impact
Materials Science and Engineering: A, 2008Co-Authors: Liang Zhen, D.l. Zou, Wenzhu ShaoAbstract:Abstract Microstructural characteristics of 1Cr18Ni9Ti stainless steel impacted by GCr15 projectiles at a velocity of 2–6 km/s was studied through the optical microscope, SEM, TEM and EBSD techniques. The experimental results show that the adiabatic shear bands beneath the crater are observed, and its width is ranging from 1 to 10 μm. The deformation twins, martensite and intersection between them are observed simultaneously under the crater, which should be attributed to the high strain rate impact. The elongated subgrains with high aspect ratio are found in the shear band, while the melt-related Microstructure is observed in the shear band. The heat converted from plastic work continuously increases the local temperature and thus leads to continued softening, even melting, in the material. According to the constitutive equation, the temperature calculated inside a shear band can be rose to the melting point of the material, which explains the melt-related Microstructure observed inside shear bands simply.
Heung Nam Han - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen-induced change in Microstructure and properties of steels: 18Cr10Mn–0.4N vis-à-vis 18Cr10Ni
Materials Science and Technology, 2017Co-Authors: Han Jin Kim, Madakashira P. Phaniraj, Min Kyung Cho, Eun Ju Song, Seung-wook Baek, Gyeung-ho Kim, Jin-yoo Suh, Joonho Lee, Heung Nam HanAbstract:ABSTRACTCr–Mn–N stainless steels have a cost and strength advantage over conventional Cr–Ni stainless steels. In this study Microstructure and mechanical property of hydrogen-charged 18Cr10Mn-0.4N was compared with 18Cr10Ni austenitic stainless steel. This is the first such study for 18Cr10Mn–0.4N austenitic stainless steel. Electron microscopy was used to compare the Deformed Microstructure of the uncharged and hydrogen-charged specimens. The results are discussed in view of the current knowledge on hydrogen embrittlement. The 18Cr10Mn–0.4N steel suffered higher embrittlement mainly because it absorbed moref hydrogen.
Indradev Samajdar - One of the best experts on this subject based on the ideXlab platform.
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Plane strain compression testing of Sanicro 28 by channel-die compression test: A direct microstructural observation
Materials Today: Proceedings, 2017Co-Authors: N. Srinivasan, Indradev Samajdar, Vivekanand Kain, K.v. Mani Krishna, P. V. SivaprasadAbstract:Abstract The split-channel plane strain die compression test was performed in Sanicro 28 (UNS N08028) high-alloy austenitic stainless steel. The same grain was examined before and after interrupted split-channel plane strain die compression tests by electron backscattered diffraction (EBSD). All Deformed specimens exhibited developments in Deformed Microstructure. The development of near boundary gradient zone (NBGZ) was quantified for specimens Deformed at different reductions. NBGZ development was gradual, it increased as a function of deformation. The image quality (IQ) map from EBSD indicated the imposed strain and formation of slip lines in the Deformed Microstructures. The inclined nature of slip lines indicated non-uniform distribution of strain and few grains did not develop any slip traces. The knowledge about NBGZ is important to enhance/control localized corrosion phenomena
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Deformed Microstructures of two-phase Zr-2.5Nb alloy: Effects of the second phase hardness
Journal of Nuclear Materials, 2010Co-Authors: Santosh K. Sahoo, Indradev Samajdar, V.d. Hiwarkar, L. Jain, Prita Pant, G.k. Dey, D. Srivastav, Tewari Rishabh, S. BanerjeeAbstract:Abstract Two types, A and B, of Zr–2.5Nb samples were subjected to compression tests. Both samples consisted of similar Microstructure – hexagonal closed packed (hcp) α phase (the primary phase) and grain boundary bcc (body centered cubic) β phase. However, the hardness of the β phase differed between the samples – respectively being hard (sample A) and soft (sample B) relative to the primary phase. This difference was caused by the presence of fine ω precipitates. The relative hardness of β phase determined almost all aspects of Deformed Microstructure developments. In sample A, the primary phase had higher lattice strain and in-grain misorientation developments. In sample B, on the other hand, the softer β phase was clearly linked to more deformation twinning and associated grain size refinement and ‘texturing’ of the hcp α phase.
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Deformation twinning in AISI 316L austenitic stainless steel: role of strain and strain path
Materials Science and Technology, 2007Co-Authors: Sushil Mishra, K. L. Narasimhan, Indradev SamajdarAbstract:AISI 316L austenitic stainless steel was Deformed at different strain and strain paths. The twin boundaries in the Deformed Microstructure had two possible origins: decay of original annealing twins and generation of deformation twins. Assuming that rotations of grains, specifically grains on both sides of a twin boundary, are responsible for the twin decay, a simple model was proposed to bring out the domain of relative twin generation. A biaxial strain path, in general, was associated with strong twin generation - an association or dependency linked to the texture estimated values of Taylor factor. Formation of strain induced martensite was also observed to be strain and strain path dependent and was more in biaxial strain path
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Recrystallization in Ultra Low Carbon (ULC) Steel: Influence of the As-Deformed Microstructure and Texture
Materials Science Forum, 1998Co-Authors: Bert Verlinden, Indradev Samajdar, Paul Van Houtte, Leo A.i. KestensAbstract:Development of recrystallization texture in an ultra low carbon (ULC) steel was studied at four (50-90%) different cold rolling reductions. During deformation, a steady increase in a fibre (RD// ) was observed, while fibre (ND// ) increased from 0-50% reduction but then did not change significantly. In the recrystallization texture, however, a steady and significant increase of γ fibre, but no changes in α, was noted with increased reductions. Based on the as Deformed state, two physical parameters were identified, which may explain the changes in recrystallization texture with strain. Those being: (1) spacings (as measured along ND) of γ/α oriented Deformed bands and (2) relative ability of such bands to form recrystallized grains. An estimation of (2) for different orientations may be obtained from their respective nucleation factors (N i , defined [6, 12] as the number of grains of a particular orientation per Deformed band of the same orientation, measured/estimated along normal direction). Evidently, a decrease in γ band spacing and/or an increase/decrease in γ/α nucleation factors will strengthen the γ recrystallization texture. With increased reductions, spacings of the γ bands decreased - mainly from the geometrical considerations. On the other hand, above 70% reduction, nucleation factors for α bands, especially for I {112} component, dropped significantly.
B.j. Pang - One of the best experts on this subject based on the ideXlab platform.
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Deformed Microstructure evolution in am60b mg alloy under hypervelocity impact at a velocity of 5 km s 1
Materials & Design, 2010Co-Authors: Dong-li Zou, Liang Zhen, Y.d. Zhu, W.z. Shao, B.j. PangAbstract:Abstract Deformed Microstructure in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s −1 were investigated through optical microscope, scanning electron microscope and transmission electron microscope. The results show that four Deformed zones around the crater can be classified based on the different Deformed Microstructure, including ultrafine grain zone, ultrafine grain and deformation twin zone, high and low density deformation twin zones. The dislocation slipping, deformation twins and ultrafine grains are the dominant components in the four Deformed zones, and the evolution of Deformed Microstructure is speculated based on the Deformed Microstructure observed in four zones. Slipping and twinning play a critical role for the formation of the dynamic recrystallized grains, and twinning-induced rotational dynamic recrystallization mechanism is thought to be the main mechanism for the formation of ultrafine grains. The microhardness and dynamic compressive strength in different Deformed zones were measured, and the high microhardness and yield strength in ultrafine grain zone should be attributed to the strain hardening and grain refining.
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Deformed Microstructure and mechanical properties of am60b magnesium alloy under hypervelocity impact at a velocity of 4 km s 1
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Liang Zhen, Chengyan Xu, Wenzhu Shao, B.j. PangAbstract:Abstract Deformed Microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s −1 were studied through optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and indenter technique. The results show that the Deformed Microstructure below the crater can be classified as three zones, i.e. dynamic recrystallization zone, high density deformation twin zone and low density deformation twin zone. The refined and equiaxed recrystallized grains adjacent to the crater were formed, which should be attributed to the twining-induced dynamic recrystallization mechanism. The { 1 0 1 ¯ 2 } , { 1 0 1 ¯ 1 } deformation twins are confirmed through selected area electron diffraction (SAED) technique. The microhardness and yield strength in the Deformed Microstructure zone near the crater are much higher than that of the matrix, which should be attributed to strain hardening and grain refining.
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Deformed Microstructure evolution in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s−1
Materials & Design, 2010Co-Authors: Dong-li Zou, Liang Zhen, Y.d. Zhu, W.z. Shao, B.j. PangAbstract:Abstract Deformed Microstructure in AM60B Mg alloy under hypervelocity impact at a velocity of 5 km s −1 were investigated through optical microscope, scanning electron microscope and transmission electron microscope. The results show that four Deformed zones around the crater can be classified based on the different Deformed Microstructure, including ultrafine grain zone, ultrafine grain and deformation twin zone, high and low density deformation twin zones. The dislocation slipping, deformation twins and ultrafine grains are the dominant components in the four Deformed zones, and the evolution of Deformed Microstructure is speculated based on the Deformed Microstructure observed in four zones. Slipping and twinning play a critical role for the formation of the dynamic recrystallized grains, and twinning-induced rotational dynamic recrystallization mechanism is thought to be the main mechanism for the formation of ultrafine grains. The microhardness and dynamic compressive strength in different Deformed zones were measured, and the high microhardness and yield strength in ultrafine grain zone should be attributed to the strain hardening and grain refining.