5083和6061铝合金异种搅拌摩擦焊接接头的组织和性能

Microstructure and Mechanical Property of Friction Stir Weld Joints of Dissimilar Al-alloys 5083 and 6061

以不同的转速对6 mm厚的5083和6061铝合金进行搅拌摩擦焊接,研究了焊接参数对接头组织和性能的影响。结果表明,控制焊接参数可获得良好的焊接质量,接头强度系数为85%。随着转速的升高5083和6061铝合金的晶粒尺寸都逐渐增大,但是在焊核区内5083铝合金的晶粒尺寸比6061铝合金的小;在6061铝合金一侧的热影响区,随着转速的增加析出相的尺寸和密度都逐渐增大。5组焊接参数的焊接接头的最低硬度区均出现在6061铝合金一侧的热影响区,随着转速的升高接头的最低硬度也逐渐提高;焊接接头均断裂在最低硬度区,且随着转速的升高接头的抗拉强度也逐渐提高。

Sheets of Al-alloys 5083 and 6061 of 6 mm in thickness were subjected to friction stir welding（FSW） with different welding parameters. The effect of welding parameters on the microstructure and mechanical property of the FSW joints were investigated. Results show that FSW joints with high quality could be produced by controlling welding parameters, and a high joint strength coefficient of 85%was obtained. Dynamic recrystallization took place in the nugget zones（NZs） with fine and equiaxed grains generated, and the grain size increased with the increasing rotation rate; usually the grain size of5083 Al in the NZ was smaller than that of 6061 Al. The heat-affected zones（HAZ） of 6061 Al side were the low hardness zones in all of the FSW joints, and the value of low hardness increased with the increasing rotation rate. It is found that the fracture paths corresponded well with the lowest hardness distribution profiles in the joints and the ultimate tensile strength increased with the increasing of the rotation rate.