1460合金的搅拌摩擦焊及焊后热处理工艺研究

采用搅拌摩擦焊对1460铝锂合金进行焊接,研究合金的焊接性能和焊后热处理工艺。运用显微硬度测试和拉伸力学性能测试表征焊缝力学性能;用扫描电镜、透射电镜对焊缝组织进行观察。结果表明:焊前对合金进行固溶和时效处理导致焊缝的抗拉强度降低;焊前未进行热处理的焊缝样品抗拉强度为320 MPa,与母材相当;焊后的固溶+160℃/40h时效处理使焊核区重新析出θ′(Al2Cu)和T1(Al2CuLi)相,焊缝的抗拉强度提高了75 MPa;焊缝拉伸断裂发生在热机械影响区,断裂方式由韧性断裂转变为解理断裂。

Study on the post-heat treatment process and the friction-stir welding of 1460 alloy

In this study,the technology of friction-stir welding of 1460 Al-Li alloy were investigated,including the mechanical properties of weld seam and the post weld heat treatments. The corresponding microstructure and mechanical properties of the weld seam were studied by means of optical microscope,scanning electron microscope,transmission electron microscope,hardness test and tensile test. Pre-weld heat treatments(aging and solution treatment)lead to the decrease of the tensile strength of the weld. The tensile strength of the weld is 320 MPa,which is equivalent to the base metal. The post-welding heat treatment(solution treated +160 ℃/40 h aging)leads to the precipitation of θ′(Al2 Cu)and T1(Al2 CuLi)observed by the transmission electron microscopy(TEM),as a result the tensile strength of the weld increased by another 75 MPa. The fracture of the weld occurs at the thermo-mechanically-affected zone,the fracture behavior of the weld changes from ductile fracture to cleavage fracture as it is post weld heat treated(aged or solution treated).