2024铝合金电子束焊接接头的显微组织与力学性能

Microstructure and Mechanical Properties of 2024 Aluminium Alloy Joint by Electron Beam Welding

采用电子束焊(EBW)对2024铝合金进行焊接,研究了接头的显微组织和力学性能。结果表明:接头焊缝显微组织呈细小的等轴晶,主要由α-Al基体相及其上分布着的θ(CuAl_2)和S(Al_2CuMg)强化相组成,热影响区为粗大的枝晶;接头的抗拉强度达到母材的80%左右,热影响区是强度最薄弱的部位;焊缝的硬度低于母材和热影响区的,且热影响区存在一定的软化现象;其拉伸断口呈典型的韧窝状断口,韧窝尺寸较小且均匀。

2024 aluminium alloy was welded by electron beam welding（EBW）.The microstructure and mechanical properties of welded joints were investigated.The results show that the microstructure of the weld zone was fine equiaxed grains,which mainly consisted ofα-Al matrix phase and a fewθ（CuAl_2.） and S（Al_2CuMg） strengthening phases,while the heat-affected zone（HAZ） was composed of coarse dendrite.The tensile strength of the welded joint was about 80%of that of the base metal,and the HAZ was the weakest area of the joint. Microhardness of the weld metal was lower than that of both the base metal and HAZ,and a softening area existed in the HAZ.The joint tensile fracture present typical dimple fracture,while the dimples were fine and distributed uniformly.