The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study.The microstructure was studied usin...The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study.The microstructure was studied using optical microscopy and electron backscatter diffraction(EBSD).Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical properties.Sound joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed increased.The EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization behavior.Specific attention was given to the relationship between the local microstructure and mechanical properties.Microhardness measurements show that the average hardness of the stir zone(SZ) was greater than that of the base material, which was only affected slightly by the travel speed.The tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.展开更多
采用自适应的热源模型,利用msc·marc模拟了6 mm 2A14铝合金的双轴肩搅拌摩擦焊温度场。随后对模拟所得的温度场进行了试验验证,在相同的工艺参数下测量了焊接过程中距焊缝不同位置处的热循环曲线和峰值温度。对比结果表明:该模型...采用自适应的热源模型,利用msc·marc模拟了6 mm 2A14铝合金的双轴肩搅拌摩擦焊温度场。随后对模拟所得的温度场进行了试验验证,在相同的工艺参数下测量了焊接过程中距焊缝不同位置处的热循环曲线和峰值温度。对比结果表明:该模型能准确地模拟双轴肩搅拌摩擦焊接过程中的温度分布情况。展开更多
The bobbin tool friction stir welding process was used to join 6 mm thick 5A06 aluminum alloy plates.Optical microscope was used to characterize the microstructure.The electron backscatter diffraction(EBSD)identified ...The bobbin tool friction stir welding process was used to join 6 mm thick 5A06 aluminum alloy plates.Optical microscope was used to characterize the microstructure.The electron backscatter diffraction(EBSD)identified the effect of non-homogeneous microstructure on the tensile properties.It was observed that the grain size in the top of the stir zone(SZ)is smaller than that in the centre region.The lowest ratio of recrystallization and density of the geometrically-necessary dislocations(GNDs)in the SZ was found in the middle near the thermo-mechanically affected zone(TMAZ)being 22%and 1.15×10^(−13) m^(−2),respectively.The texture strength of the heat-affected zone(HAZ)is the largest,followed by that in the SZ,with the lowest being in the TMAZ.There were additional interfaces developed which contributed to the strengthening mechanism,and their effect on tensile strength was analysed.The tensile tests identified the weakest part in the joint at the interfaces,and the specific reduction value is about 93 MPa.展开更多
基金financially supported by the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University, China) under Grant 2019-QZ-01。
文摘The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study.The microstructure was studied using optical microscopy and electron backscatter diffraction(EBSD).Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical properties.Sound joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed increased.The EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization behavior.Specific attention was given to the relationship between the local microstructure and mechanical properties.Microhardness measurements show that the average hardness of the stir zone(SZ) was greater than that of the base material, which was only affected slightly by the travel speed.The tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.
基金This work was financially supported by the State Key Laboratory of Solidification Processing(Northwestern Polytechnical University,China,No.2019-QZ-01)the National Natural Science Foundation of China(No.52105402)the Natural Science Foundation of Shaanxi Province(No.2021-JQ-102).
文摘The bobbin tool friction stir welding process was used to join 6 mm thick 5A06 aluminum alloy plates.Optical microscope was used to characterize the microstructure.The electron backscatter diffraction(EBSD)identified the effect of non-homogeneous microstructure on the tensile properties.It was observed that the grain size in the top of the stir zone(SZ)is smaller than that in the centre region.The lowest ratio of recrystallization and density of the geometrically-necessary dislocations(GNDs)in the SZ was found in the middle near the thermo-mechanically affected zone(TMAZ)being 22%and 1.15×10^(−13) m^(−2),respectively.The texture strength of the heat-affected zone(HAZ)is the largest,followed by that in the SZ,with the lowest being in the TMAZ.There were additional interfaces developed which contributed to the strengthening mechanism,and their effect on tensile strength was analysed.The tensile tests identified the weakest part in the joint at the interfaces,and the specific reduction value is about 93 MPa.
