6061铝合金焊接接头的组织与性能分析

通过金相技术、力学性能试验和SEM技术研究了6061-T6铝合金真空电子束焊接接头的金相组织、力学性能和断口形貌特征.结果表明:焊接接头的拉伸强度低于母材.预热和重熔可以同时降低电子束焊接接头的强度和塑性,尤其对接头的塑性影响更大.焊缝区和热影响区的硬度均低于母材,预热和重熔可以降低焊接接头的硬度.焊缝区组织主要为等轴晶和树枝柱状晶,熔合区组织主要为柱状晶.预热和重熔使得焊缝区的晶粒组织变得粗大,焊接接头的拉伸断口断面上分布的韧窝尺寸较小,且韧窝的大小接近,未发生明显的塑性流动,呈现出铸态断口特征.

A study on the microstructures and properties of the welded 6061 aluminium alloy joint

The metallurgical structures, mechanical properties and fractographs of EB welded 6061 -- T6 aluminum alloy joint were studied by means of metallography, mechanical test and SEM technology. The results showed that the tensile strength of the joint was lower than base metal. The tensile strength and plasticity of the joint was decreased by before - heating and remelfing, in which the plasticity was affected severely. The hardness of the weld seam and HAZ were also lower than base, metal and that of the joint was also decreased by before - heating and remehing. The crystallizing morphology on the weld seam was equiaxed grains and dendrites and that on the fusion area were columnar crystals. There existed grain coarsening on the weld seam hecause of before - heating and remelting. The fraetographs of the tensile specimens was cast state with many small dimples.