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D.l. Chen - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic spot welding of 5182 aluminum alloy: Evolution of microstructure and mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Shaimaa M. Mohammed, S.s. Dash, X.q. Jiang, D.l. ChenAbstract:Abstract The present study is focused on the evaluation of microstructures, tensile Lap Shear Strength and fatigue resistance of ultrasonic spot welded joints of lightweight AA 5182 aluminum alloy. The temperature quickly increased during ultrasonic spot welding (USW), with the peak temperature increasing with increasing welding energy. A “necklace”-like ultrafine structure occurred at the weld interface due to the presence of dynamic recrystallization. The tensile Lap Shear Strength increased with decreasing number of impedance setting. When the impedance was set below 5, the tensile Lap Shear failure load of nearly 6 kN was attained, surpassing the requirement for the average peak load of AWS D17.2 standards. The tensile Lap Shear Strength, failure energy, and critical stress intensity factor first increased, reached their maximum and then decreased with increasing welding energy. The maximum tensile Lap Shear Strength of ∼150 MPa was achieved at a welding energy of 4000 J and an impedance setting of 2. The load-controlled fatigue behavior displayed a bi-linear characteristic due to the change in the failure mode from interfacial failure at the higher cyclic loads to transverse-through thickness (TTT) crack growth mechanism at the lower cyclic loads.
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Ultrasonic spot welded AZ31 magnesium alloy: Microstructure, texture, and Lap Shear Strength
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: V.k. Patel, S.d. Bhole, D.l. ChenAbstract:Abstract The structural application of ultra-lightweight magnesium alloys inevitably involves welding and joining. A solid-state welding – ultrasonic spot welding (USW) – was conducted on AZ31B-H24 Mg alloy sheet by varying a key parameter of welding energy in this study, aiming to identify the changes in the microstructure, crystallographic texture, and Lap Shear tensile Strength. The grain size was observed to increase with increasing welding energy. Crystallographic texture determined via X-ray diffraction showed a significant change that corresponded well to the change in the deformation and recrystallization mechanisms of the Mg alloy. The Lap Shear Strength first increased with increasing energy input, reached the maximum value at a welding energy of 2000 J, then decreased. The welds generally fractured along the joint interface when the welding energy was lower than 2000 J, while fracture occurred at the periphery of the joint (button pull-out) for the samples made with an energy input of higher than 2000 J.
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Lap Shear Strength and fatigue behavior of friction stir spot welded dissimilar magnesium to aluminum joints with adhesive
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: S. H. Chowdhury, D.l. Chen, S.d. Bhole, P. WanjaraAbstract:Abstract Lightweighting is currently considered as an effective way in improving fuel efficiency and reducing anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the aerospace and automotive sectors unavoidably involve welding and joining while guaranteeing the safety and durability of motor vehicles. The objective of this study was to evaluate the Lap Shear Strength and fatigue properties of friction stir spot welded (FSSWed) dissimilar AZ31B-H24 Mg alloy and Al alloy (AA) 5754-O in three combinations, i.e., (top) Al/Mg (bottom), Al/Mg with an adhesive interlayer, and Mg/Al with an adhesive interlayer. For all the dissimilar Mg-to-Al weld combinations, FSSW induced an interfacial layer in the stir zone (SZ) that was composed of intermetallic compounds of Al3Mg2 and Al12Mg17, which led to an increase in hardness. Both Mg/Al and Al/Mg dissimilar adhesive welds had significantly higher Lap Shear Strength, failure energy and fatigue life than the Al/Mg dissimilar weld without adhesive. Two different types of fatigue failure modes were observed. In the Al/Mg adhesive weld, at high cyclic loads nugget pull-out failure occurred due to fatigue crack propagation circumferentially around the nugget. At low cyclic loads, fatigue failure occurred in the bottom Mg sheet due to the stress concentration of the keyhole leading to crack initiation followed by propagation perpendicular to the loading direction. In the Mg/Al adhesive weld, nugget pull-out failure mode was primarily observed at both high and low cyclic loads.
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Lap Shear Strength and fatigue life of friction stir spot welded AZ31 magnesium and 5754 aluminum alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: S. H. Chowdhury, D.l. Chen, S.d. Bhole, Xinjin Cao, P. WanjaraAbstract:Abstract Lightweighting is today considered as one of the key strategies in reducing fuel consumption and anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the transportation industry inevitably involve welding and joining while guaranteeing the safety and reliability of motor vehicles. This study was aimed at evaluating Lap Shear Strength and fatigue properties of friction stir spot welded (FSSWed) AZ31B-H24 Mg and 5754-O Al alloys in three combinations, i.e., similar Mg-to-Mg, Al-to-Al, and dissimilar Al-to-Mg joints. The Mg/Mg similar weld had a nugget-shaped stir zone (SZ) around the keyhole where fine recrytallized equiaxed grains were observed. While the hardness profile of the Mg/Mg similar weld exhibited a W-shaped appearance, the lower hardness values appeared in the TMAZ and HAZ of both Mg/Mg and Al/Al similar welds. In the Al/Mg dissimilar weld, a characteristic interfacial layer consisting of intermetallic compounds (IMC) Al 12 Mg 17 and Al 3 Mg 2 was observed. Both Mg/Mg and Al/Al similar welds had significantly higher Lap Shear Strength, failure energy and fatigue life than the Al/Mg dissimilar weld. While the Al/Al weld displayed a slightly lower Lap Shear Strength than the Mg/Mg weld, the Al/Al weld had higher failure energy and fatigue life. Three types of failure modes were observed. In the Mg/Mg and Al/Al similar welds, at higher cyclic loads nugget pullout failure occurred due to fatigue crack propagation circumferentially around the nugget, while at lower cyclic loads fatigue failure occurred perpendicular to the loading direction caused by the opening of keyhole through crack initiation in the TMAZ and HAZ. In the Al/Mg dissimilar weld nugget debonding failure mode was observed because of the presence of an interfacial IMC layer.
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microstructure and mechanical properties of dissimilar welded mg al joints by ultrasonic spot welding technique
Science and Technology of Welding and Joining, 2012Co-Authors: V.k. Patel, S.d. Bhole, D.l. ChenAbstract:Dissimilar spot welds of magnesium–aluminium alloy were produced via a solid state welding process, i.e. ultrasonic spot welding, and a sound joint was obtained under most of the welding conditions. It was observed that a layer of intermetallic compound (IMC) consisting of Al12M17 formed at the weld centre where the hardness became higher. The Lap Shear Strength and failure energy of the welds first increased and then decreased with increasing welding energy, with the maximum Lap Shear Strength and failure energy occurring at ∼1250 J. This was a consequence of the competition between the increasing diffusion bonding arising from higher temperatures and the deterioration effect of the intermetallic layer of increasing thicknesses. Failure predominantly occurred in between the aluminium alloy and the intermetallic layer, which normally stayed at the magnesium side or from the cracks of the IMCs in the reaction layer.
Hiroyuki Kokawa - One of the best experts on this subject based on the ideXlab platform.
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microstructure and Lap Shear Strength of the weld interface in ultrasonic welding of al alloy to stainless steel
Scripta Materialia, 2016Co-Authors: Hiromichi T Fujii, Yuta Goto, Y Sato, Hiroyuki KokawaAbstract:Abstract Dissimilar welds between Al alloy and stainless steel were produced with an ultrasonic welding technique. The weld Strength increased with the welding energy. The welds produced with sufficiently high energy exhibited nugget pull-out failure of the Al alloy during the Lap Shear Strength test. The welds with weld energies of more than 1.05 kJ fractured in the base metal and were severely deformed by the ultrasonic vibration, and recrystallization occurred around the weld interface owing to the Shear deformation and heating during the ultrasonic welding.
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Effect of interfacial microstructure on Lap Shear Strength of friction stir spot weld of aluminium alloy to magnesium alloy
Science and Technology of Welding and Joining, 2010Co-Authors: Yutaka S. Sato, A. Shiota, Hiroyuki Kokawa, K. Okamoto, Q. Yang, C. KimAbstract:AbstractIn the present study, an attempt was made to join two dissimilar light metal alloys which are becoming increasingly familiar in the automotive industry, i.e. AA5083 aluminium alloy and AZ31 magnesium alloy, by the friction stir spot welding process. Lap welds were produced with various welding parameters, and interfacial microstructures and Lap Shear Strengths of these welds were examined. Friction stir spot welding produced defect-free welds, even though a thick interfacial layer composed mainly of intermetallic compounds was present. The thickness of the interfacial layer did not appear to affect the Lap Shear Strength of the weld, whereas the distribution of intermetallic compounds in the interfacial layer did so. Microstructural factors of the interface governing the Lap Shear Strength of the weld were examined.
Klaus Drechsler - One of the best experts on this subject based on the ideXlab platform.
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Steel-CF/PA 6 hybrids manufactured by a laser tape placement process: Effect of first-ply placement rate on Lap Shear Strength for garnet blasted substrates
Procedia Manufacturing, 2019Co-Authors: Christopher Stokes-griffin, A. Kollmannsberger, Paul Compston, Klaus DrechslerAbstract:Abstract This paper investigates the manufacture of selectively reinforced metal/composite hybrids in a laser-assisted automated tape placement process. Unidirectional carbon fibre/PA 6 composite tapes were applied to 1.9 mm hot rolled steel substrates. The bonding of the first ply to the substrate is critical to the success of the metal-composite hybrid. This work investigates the effect of increasing the first-ply placement rate for speeds of 25 mm/s, 50 mm/s and 100 mm/s. The steel substrates were pre-treated by garnet blasting and then coating with a 60 μm layer of PA 6. The garnet blasted surface texture was quantified using white light interferometry. The thermal history for bonding of the first ply was measured with fine wire thermocouples. The interfacial bond Strength of the hybrid laminates was assessed by ASTM D 3165 Lap Shear tests. The Lap Shear Strength increased to the highest value of 22.4 MPa at 50 mm/s. Analysis of the fracture surfaces and thermal history suggest that the lower Strengths at 25 mm/s and 100 mm/s are due to lower adhesion of the PA 6 coating to the metal substrate, most probably due to lower levels of crystallization.
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Manufacture of steel–CF/PA6 hybrids in a laser tape placement process: Effect of first-ply placement rate on thermal history and Lap Shear Strength
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Christopher Stokes-griffin, A. Kollmannsberger, S. Ehard, Paul Compston, Klaus DrechslerAbstract:Abstract This paper investigates the manufacture of selectively reinforced metal/composite hybrids in a laser-assisted automated tape placement process. Carbon-fibre/PA6 composite tapes were applied to PA6-coated steel substrates. The bonding of the first-ply to the substrate is critical to the success of the hybrid; the effect of first-ply placement rate was investigated for speeds of 25 mm/s, 50 mm/s, 100 mm/s. The interfacial bond Strength of the hybrid laminates was determined by ASTM D 3165 Lap Shear tests. A 3D finite element thermal model was formulated to elucidate the thermal behaviour for increasing first-ply placement rate. A method for increasing model efficiency was shown to significantly decrease the computational difficulty while maintaining solution accuracy. Raising the first-ply placement rate from 25 mm/s to 100 mm/s resulted in a fourfold increase in Lap Shear Strength with a maximum value of 22 MPa. The greater Strength at higher speeds is attributed to improved synchronisation of the temperature and consolidation pressure history.
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manufacture of steel cf pa6 hybrids in a laser tape placement process effect of first ply placement rate on thermal history and Lap Shear Strength
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Christopher Stokesgriffin, A. Kollmannsberger, S. Ehard, Paul Compston, Klaus DrechslerAbstract:Abstract This paper investigates the manufacture of selectively reinforced metal/composite hybrids in a laser-assisted automated tape placement process. Carbon-fibre/PA6 composite tapes were applied to PA6-coated steel substrates. The bonding of the first-ply to the substrate is critical to the success of the hybrid; the effect of first-ply placement rate was investigated for speeds of 25 mm/s, 50 mm/s, 100 mm/s. The interfacial bond Strength of the hybrid laminates was determined by ASTM D 3165 Lap Shear tests. A 3D finite element thermal model was formulated to elucidate the thermal behaviour for increasing first-ply placement rate. A method for increasing model efficiency was shown to significantly decrease the computational difficulty while maintaining solution accuracy. Raising the first-ply placement rate from 25 mm/s to 100 mm/s resulted in a fourfold increase in Lap Shear Strength with a maximum value of 22 MPa. The greater Strength at higher speeds is attributed to improved synchronisation of the temperature and consolidation pressure history.
Martine Dubé - One of the best experts on this subject based on the ideXlab platform.
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Effects of environmental conditions on the Lap Shear Strength of resistance-welded carbon fibre/thermoplastic composite joints
Composites Part B-engineering, 2020Co-Authors: Vincent Rohart, Louis Laberge Lebel, Martine DubéAbstract:Abstract The objective of this study is to understand the influence of temperature and moisture on the Lap Shear Strength (LSS) of carbon fibre/polyphenylene sulfide (CF/PPS) resistance-welded joints. The welded joints are conditioned at various levels of temperature and humidity and tested at temperatures ranging from 21 °C to 150 °C. Temperature is shown to have an effect on the LSS with a reduction of 26% at 82 °C and 61% at 150 °C (around 60 °C above the PPS Tg), relative to room temperature. Moisture is shown to have little to no impact on the LSS, due to the semi-crystalline nature of PPS and its good resistance to water absorption. Observation of the joints’ fracture surfaces shows a degradation of the fibre/matrix interface under severe environmental conditions and a failure mode involving both fibre/matrix and heating element/matrix debonding.
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effects of environmental conditions on the Lap Shear Strength of resistance welded carbon fibre thermoplastic composite joints
Composites Part B-engineering, 2020Co-Authors: Vincent Rohart, Louis Laberge Lebel, Martine DubéAbstract:Abstract The objective of this study is to understand the influence of temperature and moisture on the Lap Shear Strength (LSS) of carbon fibre/polyphenylene sulfide (CF/PPS) resistance-welded joints. The welded joints are conditioned at various levels of temperature and humidity and tested at temperatures ranging from 21 °C to 150 °C. Temperature is shown to have an effect on the LSS with a reduction of 26% at 82 °C and 61% at 150 °C (around 60 °C above the PPS Tg), relative to room temperature. Moisture is shown to have little to no impact on the LSS, due to the semi-crystalline nature of PPS and its good resistance to water absorption. Observation of the joints’ fracture surfaces shows a degradation of the fibre/matrix interface under severe environmental conditions and a failure mode involving both fibre/matrix and heating element/matrix debonding.
S.d. Bhole - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic spot welded AZ31 magnesium alloy: Microstructure, texture, and Lap Shear Strength
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: V.k. Patel, S.d. Bhole, D.l. ChenAbstract:Abstract The structural application of ultra-lightweight magnesium alloys inevitably involves welding and joining. A solid-state welding – ultrasonic spot welding (USW) – was conducted on AZ31B-H24 Mg alloy sheet by varying a key parameter of welding energy in this study, aiming to identify the changes in the microstructure, crystallographic texture, and Lap Shear tensile Strength. The grain size was observed to increase with increasing welding energy. Crystallographic texture determined via X-ray diffraction showed a significant change that corresponded well to the change in the deformation and recrystallization mechanisms of the Mg alloy. The Lap Shear Strength first increased with increasing energy input, reached the maximum value at a welding energy of 2000 J, then decreased. The welds generally fractured along the joint interface when the welding energy was lower than 2000 J, while fracture occurred at the periphery of the joint (button pull-out) for the samples made with an energy input of higher than 2000 J.
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Lap Shear Strength and fatigue behavior of friction stir spot welded dissimilar magnesium to aluminum joints with adhesive
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: S. H. Chowdhury, D.l. Chen, S.d. Bhole, P. WanjaraAbstract:Abstract Lightweighting is currently considered as an effective way in improving fuel efficiency and reducing anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the aerospace and automotive sectors unavoidably involve welding and joining while guaranteeing the safety and durability of motor vehicles. The objective of this study was to evaluate the Lap Shear Strength and fatigue properties of friction stir spot welded (FSSWed) dissimilar AZ31B-H24 Mg alloy and Al alloy (AA) 5754-O in three combinations, i.e., (top) Al/Mg (bottom), Al/Mg with an adhesive interlayer, and Mg/Al with an adhesive interlayer. For all the dissimilar Mg-to-Al weld combinations, FSSW induced an interfacial layer in the stir zone (SZ) that was composed of intermetallic compounds of Al3Mg2 and Al12Mg17, which led to an increase in hardness. Both Mg/Al and Al/Mg dissimilar adhesive welds had significantly higher Lap Shear Strength, failure energy and fatigue life than the Al/Mg dissimilar weld without adhesive. Two different types of fatigue failure modes were observed. In the Al/Mg adhesive weld, at high cyclic loads nugget pull-out failure occurred due to fatigue crack propagation circumferentially around the nugget. At low cyclic loads, fatigue failure occurred in the bottom Mg sheet due to the stress concentration of the keyhole leading to crack initiation followed by propagation perpendicular to the loading direction. In the Mg/Al adhesive weld, nugget pull-out failure mode was primarily observed at both high and low cyclic loads.
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Lap Shear Strength and fatigue life of friction stir spot welded AZ31 magnesium and 5754 aluminum alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: S. H. Chowdhury, D.l. Chen, S.d. Bhole, Xinjin Cao, P. WanjaraAbstract:Abstract Lightweighting is today considered as one of the key strategies in reducing fuel consumption and anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the transportation industry inevitably involve welding and joining while guaranteeing the safety and reliability of motor vehicles. This study was aimed at evaluating Lap Shear Strength and fatigue properties of friction stir spot welded (FSSWed) AZ31B-H24 Mg and 5754-O Al alloys in three combinations, i.e., similar Mg-to-Mg, Al-to-Al, and dissimilar Al-to-Mg joints. The Mg/Mg similar weld had a nugget-shaped stir zone (SZ) around the keyhole where fine recrytallized equiaxed grains were observed. While the hardness profile of the Mg/Mg similar weld exhibited a W-shaped appearance, the lower hardness values appeared in the TMAZ and HAZ of both Mg/Mg and Al/Al similar welds. In the Al/Mg dissimilar weld, a characteristic interfacial layer consisting of intermetallic compounds (IMC) Al 12 Mg 17 and Al 3 Mg 2 was observed. Both Mg/Mg and Al/Al similar welds had significantly higher Lap Shear Strength, failure energy and fatigue life than the Al/Mg dissimilar weld. While the Al/Al weld displayed a slightly lower Lap Shear Strength than the Mg/Mg weld, the Al/Al weld had higher failure energy and fatigue life. Three types of failure modes were observed. In the Mg/Mg and Al/Al similar welds, at higher cyclic loads nugget pullout failure occurred due to fatigue crack propagation circumferentially around the nugget, while at lower cyclic loads fatigue failure occurred perpendicular to the loading direction caused by the opening of keyhole through crack initiation in the TMAZ and HAZ. In the Al/Mg dissimilar weld nugget debonding failure mode was observed because of the presence of an interfacial IMC layer.
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microstructure and mechanical properties of dissimilar welded mg al joints by ultrasonic spot welding technique
Science and Technology of Welding and Joining, 2012Co-Authors: V.k. Patel, S.d. Bhole, D.l. ChenAbstract:Dissimilar spot welds of magnesium–aluminium alloy were produced via a solid state welding process, i.e. ultrasonic spot welding, and a sound joint was obtained under most of the welding conditions. It was observed that a layer of intermetallic compound (IMC) consisting of Al12M17 formed at the weld centre where the hardness became higher. The Lap Shear Strength and failure energy of the welds first increased and then decreased with increasing welding energy, with the maximum Lap Shear Strength and failure energy occurring at ∼1250 J. This was a consequence of the competition between the increasing diffusion bonding arising from higher temperatures and the deterioration effect of the intermetallic layer of increasing thicknesses. Failure predominantly occurred in between the aluminium alloy and the intermetallic layer, which normally stayed at the magnesium side or from the cracks of the IMCs in the reaction layer.
