This study was performed to investigate microstructure of dissimilar friction stir welds manufactured with AA6061-T6 and AZ31 alloy sheets. Dissimilar butt joints were fabricated under the ＇off-set＇ condition that t...This study was performed to investigate microstructure of dissimilar friction stir welds manufactured with AA6061-T6 and AZ31 alloy sheets. Dissimilar butt joints were fabricated under the ＇off-set＇ condition that tool plunge position shifted toward AZ31 from the interface between AA6061-T6 and AZ31. Optimized tool rotating speed and its traveling speed were selected through a lot of preliminary experiments. Electron back-scatter diffraction （EBSD） technique was applied to measure texture in the stir zone （SZ）. Grain size distribution and misorientation angle distribution were also obtained. A remarkably fine-grained microstructure was observed in the SZ. Randomized or weaker plane orientations were formed in the SZ of AA6061-T6, while rotated basal plane orientations were concentrated in the SZ of AZ31. Average size of recrystallized grains was measured as just 2.5—4.5 μm. The fraction of high-angle boundary in the SZ of AA6061-T6 increased and that of low-angle boundary in the SZ of AZ31 decreased compared with the base metals.展开更多
Dissimilar friction stir welding between AZ31-O Mg and 6061-T6 Al alloys was investigated. 3 mm thick plates of aluminum and magnesium were used. Friction stir welding operations were performed at different rotation a...Dissimilar friction stir welding between AZ31-O Mg and 6061-T6 Al alloys was investigated. 3 mm thick plates of aluminum and magnesium were used. Friction stir welding operations were performed at different rotation and travel speeds. The rotation speeds varied from 600 to 1400 r/min, and the travel speed varied from 20 to 60 mm/min. Defect-free weld was obtained with a rotation speed of 1000 r/min and travel speed of 40 mm/min. Metallographic studies showed that the grain size in the stir zone is much finer than that in the base metals. Complex flow pattern was formed in the stir zone. Microhardness measurement revealed an uneven distribution in the stir zone. Tensile test results indicated that the tensile strength of the welded specimen is about 76% of AZ31 Mg alloy and 60% of the 6061 Al alloy in tensile strength. SEM fracture surface image of the welded specimen indicated that the welded specimen failed through brittle-mode fracture.展开更多
A 6061 Al coating for AZ31 Mg alloy was prepared by multi-pass friction stir welding(FSW)with different travel speeds.The mi-crostructure,mechanical properties of the interfacial region and the corrosion behavior of t...A 6061 Al coating for AZ31 Mg alloy was prepared by multi-pass friction stir welding(FSW)with different travel speeds.The mi-crostructure,mechanical properties of the interfacial region and the corrosion behavior of the coating were investigated systematically.The results indicate that the interfacial intermetallic compounds formed in the stir zone(SZ)consist of mainly Al12Mg17 and Al3Mg2.The inter-metallic compounds in the SZ are significantly increased when the travel speed is increased from 30 mm/min to 60 mm/min.Microhardness measurements and results of shear-tensile tests show that the mechanical properties are influenced by the intermetallic compounds formed in the SZ during FSW.Corrosion tests indicate that the 6061 Al coating can significantly improve the corrosion resistance of AZ31 plate.The 6061 Al coating obtained with a travel speed of 30 mm/min has a maximum corrosion potential E corr of-0.503 V VSE.展开更多
基金supported by the Korea Institute of Industrial Technology (KITECH)the KITECH for financial support
文摘This study was performed to investigate microstructure of dissimilar friction stir welds manufactured with AA6061-T6 and AZ31 alloy sheets. Dissimilar butt joints were fabricated under the ＇off-set＇ condition that tool plunge position shifted toward AZ31 from the interface between AA6061-T6 and AZ31. Optimized tool rotating speed and its traveling speed were selected through a lot of preliminary experiments. Electron back-scatter diffraction （EBSD） technique was applied to measure texture in the stir zone （SZ）. Grain size distribution and misorientation angle distribution were also obtained. A remarkably fine-grained microstructure was observed in the SZ. Randomized or weaker plane orientations were formed in the SZ of AA6061-T6, while rotated basal plane orientations were concentrated in the SZ of AZ31. Average size of recrystallized grains was measured as just 2.5—4.5 μm. The fraction of high-angle boundary in the SZ of AA6061-T6 increased and that of low-angle boundary in the SZ of AZ31 decreased compared with the base metals.
文摘Dissimilar friction stir welding between AZ31-O Mg and 6061-T6 Al alloys was investigated. 3 mm thick plates of aluminum and magnesium were used. Friction stir welding operations were performed at different rotation and travel speeds. The rotation speeds varied from 600 to 1400 r/min, and the travel speed varied from 20 to 60 mm/min. Defect-free weld was obtained with a rotation speed of 1000 r/min and travel speed of 40 mm/min. Metallographic studies showed that the grain size in the stir zone is much finer than that in the base metals. Complex flow pattern was formed in the stir zone. Microhardness measurement revealed an uneven distribution in the stir zone. Tensile test results indicated that the tensile strength of the welded specimen is about 76% of AZ31 Mg alloy and 60% of the 6061 Al alloy in tensile strength. SEM fracture surface image of the welded specimen indicated that the welded specimen failed through brittle-mode fracture.
基金The authors acknowledge financial support by the National Natural Science Foundation(Project No.51601024)the National Key Research and Development Program of China(Project No.2016YFB0700403)+2 种基金the Chongqing Research Program of Basic Research and Frontier Technology(Project No.cstc2019jcyj-msxmX0306)the Fundamental Research Funds for the Central Universities(Project Nos.2019CDXYCL0031,2018CDJDCL0019,2018CDJDCD0001,and 2018CDGFCL0005)the support of the 111 Project(Project No.B16007)by the Ministry of Education and the State Administration of Foreign Experts Affairs of China.
文摘A 6061 Al coating for AZ31 Mg alloy was prepared by multi-pass friction stir welding(FSW)with different travel speeds.The mi-crostructure,mechanical properties of the interfacial region and the corrosion behavior of the coating were investigated systematically.The results indicate that the interfacial intermetallic compounds formed in the stir zone(SZ)consist of mainly Al12Mg17 and Al3Mg2.The inter-metallic compounds in the SZ are significantly increased when the travel speed is increased from 30 mm/min to 60 mm/min.Microhardness measurements and results of shear-tensile tests show that the mechanical properties are influenced by the intermetallic compounds formed in the SZ during FSW.Corrosion tests indicate that the 6061 Al coating can significantly improve the corrosion resistance of AZ31 plate.The 6061 Al coating obtained with a travel speed of 30 mm/min has a maximum corrosion potential E corr of-0.503 V VSE.
