The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform
X Cao - One of the best experts on this subject based on the ideXlab platform.
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tensile properties of a friction stir welded magnesium alloy effect of pin tool Thread orientation and weld pitch
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: S M Chowdhury, D L Chen, S D Bhole, X CaoAbstract:Abstract Microstructures, tensile properties and strain hardening behavior of a friction stir welded (FSWed) AZ31B-H24 magnesium alloy were studied at varying welding speeds, rotational rates and pin tool Thread orientations. After friction stir welding (FSW) both yield strength (YS) and ultimate tensile strength (UTS) were observed to be lower but strain hardening exponent became much higher due to the presence of recrystallized grains in the stirred zone (SZ) and thermomechanically affected zone (TMAZ). The left-Hand Thread pin tool rotating clockwise generated good FSWed joints and mechanical properties due to the downward material flow close to the pin surface, while the right-Hand Thread pin tool turning clockwise caused an upward material flow and resulted in inferior joints. The YS and UTS increased and strain hardening exponent decreased with increasing welding speed. The YS as a function of grain sizes obeyed the Hall-Petch relationship well, and it also increased with decreasing rotational rate. Both YS and UTS were observed to increase linearly with increasing weld pitch (a ratio of welding speed to rotational rate). A significantly higher YS of ∼170 MPa was achieved at a high weld pitch of 1.2 mm/rev, in comparison with that (∼110 MPa) using a weld pitch ranging from 0.0039 to 0.24 mm/rev. All the FSWed AZ31B-H24 joints failed in-between the SZ and TMAZ. Dimple-like ductile fracture characteristics appeared in the base metal, while some cleavage-like flat facets together with dimples and river marking were observed in the FSWed samples.
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Effect of pin tool Thread orientation on fatigue strength of friction stir welded AZ31B-H24 Mg butt joints
Procedia Engineering, 2010Co-Authors: S M Chowdhury, S D Bhole, Daolun Chen, X CaoAbstract:Abstract The aim of this investigation was to evaluate the fatigue resistance of friction stir welded (FSWed) AZ31B-H24 Mg alloy butt joints with emphasis on the effect of pin tool Thread orientation (right-Hand Thread (RHT) and left-Hand Thread (LHT)) in the clockwise rotation. The friction stir welding resulted in recrystallized grains in the stir zone (SZ) and thermomechanicallyaffected zone (TMAZ), and partially recrystallized grains in the heat-affected zone (HAZ), with the lowest hardness appeared in the SZ. The fatigue life after friction stir welding was observed to be lower at high stress amplitudes, but remained nearly the same at low stress amplitudes. Fatigue strength was higher in the FSWed joints made with the LHT pin tool than with the RHT pin tool due to the elimination of the welding defects near the bottom surface via a downward material flow. Fatigue fracture basically occurred at or near the boundary between TMAZ and SZ. Fatigue crack initiated from the specimen surface or near surface defects in the case of LHT pin tool, and from the welding defects near the bottom surface in the case of RHT pin tool. Crack propagation was characterized by the formation of fatigue striations.
S M Chowdhury - One of the best experts on this subject based on the ideXlab platform.
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tensile properties of a friction stir welded magnesium alloy effect of pin tool Thread orientation and weld pitch
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: S M Chowdhury, D L Chen, S D Bhole, X CaoAbstract:Abstract Microstructures, tensile properties and strain hardening behavior of a friction stir welded (FSWed) AZ31B-H24 magnesium alloy were studied at varying welding speeds, rotational rates and pin tool Thread orientations. After friction stir welding (FSW) both yield strength (YS) and ultimate tensile strength (UTS) were observed to be lower but strain hardening exponent became much higher due to the presence of recrystallized grains in the stirred zone (SZ) and thermomechanically affected zone (TMAZ). The left-Hand Thread pin tool rotating clockwise generated good FSWed joints and mechanical properties due to the downward material flow close to the pin surface, while the right-Hand Thread pin tool turning clockwise caused an upward material flow and resulted in inferior joints. The YS and UTS increased and strain hardening exponent decreased with increasing welding speed. The YS as a function of grain sizes obeyed the Hall-Petch relationship well, and it also increased with decreasing rotational rate. Both YS and UTS were observed to increase linearly with increasing weld pitch (a ratio of welding speed to rotational rate). A significantly higher YS of ∼170 MPa was achieved at a high weld pitch of 1.2 mm/rev, in comparison with that (∼110 MPa) using a weld pitch ranging from 0.0039 to 0.24 mm/rev. All the FSWed AZ31B-H24 joints failed in-between the SZ and TMAZ. Dimple-like ductile fracture characteristics appeared in the base metal, while some cleavage-like flat facets together with dimples and river marking were observed in the FSWed samples.
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Effect of pin tool Thread orientation on fatigue strength of friction stir welded AZ31B-H24 Mg butt joints
Procedia Engineering, 2010Co-Authors: S M Chowdhury, S D Bhole, Daolun Chen, X CaoAbstract:Abstract The aim of this investigation was to evaluate the fatigue resistance of friction stir welded (FSWed) AZ31B-H24 Mg alloy butt joints with emphasis on the effect of pin tool Thread orientation (right-Hand Thread (RHT) and left-Hand Thread (LHT)) in the clockwise rotation. The friction stir welding resulted in recrystallized grains in the stir zone (SZ) and thermomechanicallyaffected zone (TMAZ), and partially recrystallized grains in the heat-affected zone (HAZ), with the lowest hardness appeared in the SZ. The fatigue life after friction stir welding was observed to be lower at high stress amplitudes, but remained nearly the same at low stress amplitudes. Fatigue strength was higher in the FSWed joints made with the LHT pin tool than with the RHT pin tool due to the elimination of the welding defects near the bottom surface via a downward material flow. Fatigue fracture basically occurred at or near the boundary between TMAZ and SZ. Fatigue crack initiated from the specimen surface or near surface defects in the case of LHT pin tool, and from the welding defects near the bottom surface in the case of RHT pin tool. Crack propagation was characterized by the formation of fatigue striations.
S D Bhole - One of the best experts on this subject based on the ideXlab platform.
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tensile properties of a friction stir welded magnesium alloy effect of pin tool Thread orientation and weld pitch
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: S M Chowdhury, D L Chen, S D Bhole, X CaoAbstract:Abstract Microstructures, tensile properties and strain hardening behavior of a friction stir welded (FSWed) AZ31B-H24 magnesium alloy were studied at varying welding speeds, rotational rates and pin tool Thread orientations. After friction stir welding (FSW) both yield strength (YS) and ultimate tensile strength (UTS) were observed to be lower but strain hardening exponent became much higher due to the presence of recrystallized grains in the stirred zone (SZ) and thermomechanically affected zone (TMAZ). The left-Hand Thread pin tool rotating clockwise generated good FSWed joints and mechanical properties due to the downward material flow close to the pin surface, while the right-Hand Thread pin tool turning clockwise caused an upward material flow and resulted in inferior joints. The YS and UTS increased and strain hardening exponent decreased with increasing welding speed. The YS as a function of grain sizes obeyed the Hall-Petch relationship well, and it also increased with decreasing rotational rate. Both YS and UTS were observed to increase linearly with increasing weld pitch (a ratio of welding speed to rotational rate). A significantly higher YS of ∼170 MPa was achieved at a high weld pitch of 1.2 mm/rev, in comparison with that (∼110 MPa) using a weld pitch ranging from 0.0039 to 0.24 mm/rev. All the FSWed AZ31B-H24 joints failed in-between the SZ and TMAZ. Dimple-like ductile fracture characteristics appeared in the base metal, while some cleavage-like flat facets together with dimples and river marking were observed in the FSWed samples.
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Effect of pin tool Thread orientation on fatigue strength of friction stir welded AZ31B-H24 Mg butt joints
Procedia Engineering, 2010Co-Authors: S M Chowdhury, S D Bhole, Daolun Chen, X CaoAbstract:Abstract The aim of this investigation was to evaluate the fatigue resistance of friction stir welded (FSWed) AZ31B-H24 Mg alloy butt joints with emphasis on the effect of pin tool Thread orientation (right-Hand Thread (RHT) and left-Hand Thread (LHT)) in the clockwise rotation. The friction stir welding resulted in recrystallized grains in the stir zone (SZ) and thermomechanicallyaffected zone (TMAZ), and partially recrystallized grains in the heat-affected zone (HAZ), with the lowest hardness appeared in the SZ. The fatigue life after friction stir welding was observed to be lower at high stress amplitudes, but remained nearly the same at low stress amplitudes. Fatigue strength was higher in the FSWed joints made with the LHT pin tool than with the RHT pin tool due to the elimination of the welding defects near the bottom surface via a downward material flow. Fatigue fracture basically occurred at or near the boundary between TMAZ and SZ. Fatigue crack initiated from the specimen surface or near surface defects in the case of LHT pin tool, and from the welding defects near the bottom surface in the case of RHT pin tool. Crack propagation was characterized by the formation of fatigue striations.
D L Chen - One of the best experts on this subject based on the ideXlab platform.
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tensile properties of a friction stir welded magnesium alloy effect of pin tool Thread orientation and weld pitch
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: S M Chowdhury, D L Chen, S D Bhole, X CaoAbstract:Abstract Microstructures, tensile properties and strain hardening behavior of a friction stir welded (FSWed) AZ31B-H24 magnesium alloy were studied at varying welding speeds, rotational rates and pin tool Thread orientations. After friction stir welding (FSW) both yield strength (YS) and ultimate tensile strength (UTS) were observed to be lower but strain hardening exponent became much higher due to the presence of recrystallized grains in the stirred zone (SZ) and thermomechanically affected zone (TMAZ). The left-Hand Thread pin tool rotating clockwise generated good FSWed joints and mechanical properties due to the downward material flow close to the pin surface, while the right-Hand Thread pin tool turning clockwise caused an upward material flow and resulted in inferior joints. The YS and UTS increased and strain hardening exponent decreased with increasing welding speed. The YS as a function of grain sizes obeyed the Hall-Petch relationship well, and it also increased with decreasing rotational rate. Both YS and UTS were observed to increase linearly with increasing weld pitch (a ratio of welding speed to rotational rate). A significantly higher YS of ∼170 MPa was achieved at a high weld pitch of 1.2 mm/rev, in comparison with that (∼110 MPa) using a weld pitch ranging from 0.0039 to 0.24 mm/rev. All the FSWed AZ31B-H24 joints failed in-between the SZ and TMAZ. Dimple-like ductile fracture characteristics appeared in the base metal, while some cleavage-like flat facets together with dimples and river marking were observed in the FSWed samples.
Daniel Schmitt - One of the best experts on this subject based on the ideXlab platform.
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The Evolution of the Primate Hand - The Evolution of the Primate Hand: Anatomical, Developmental, Functional, and Paleontological Evidence
Developments in Primatology: Progress and Prospects, 2016Co-Authors: Tracy L. Kivell, Pierre Lemelin, Brian G. Richmond, Daniel SchmittAbstract:This book demonstrates how the primate Hand combines both primitive and novel morphology, both general function with specialization, and both a remarkable degree of diversity within some clades and yet general similarity across many others. Across the chapters, different authors have addressed a variety of specific questions and provided their perspectives, but all explore the main themes described above to provide an overarching “primitive primate Hand” Thread to the book. Each chapter provides an in-depth review and critical account of the available literature, a balanced interpretation of the evidence from a variety of perspectives, and prospects for future research questions. In order to make this a useful resource for researchers at all levels, the basic structure of each chapter is the same, so that information can be easily consulted from chapter to chapter. An extensive reference list is provided at the end of each chapter so the reader has additional resources to address more specific questions or to find specific data.
