摘要
采用搅拌摩擦焊方法对6mm厚7A60-T6超高强铝合金进行了焊接试验,分析讨论了接头的显微组织和力学性能。结果表明:接头焊核区组织发生了动态再结晶,形成了细小的等轴再结晶晶粒,同时析出相大部分固溶入基体,热影响区晶粒粗化,在晶界处析出大量的析出相,前进侧热机影响区晶粒发生了较大程度的变形,后退侧晶粒变形程度较小;在旋转速率为300r·min-1、焊接速率为100mm·min-1或旋转速率为600r·min-1、焊接速率为300mm·min-1时,接头的抗拉强度分别达到了465MPa和464MPa,可达母材抗拉强度的70%;接头微观断口中存在大量的小韧窝且韧窝较浅偏脆性,其断裂形式为韧性为主脆性为辅的混合型断裂;接头上表面的显微硬度高于接头横截面的硬度,焊核区上部硬度高于下部硬度。
Microstructures and mechanical properties of the whole specimen in 6 mm thickness TA60 T6 aluminium alloy plate joints obtained by friction stir welding （FSW） were studied. The results show that fine equiaxed and recrystallized grains could be observed in the weld nugget zone（WNZ）, and the segregation phases mostly dissolved into the matrix. The microstructure of the heat affected zone（HAZ） consisted of coarse bar-shape recovery grain, and a large number of segregation phases appeared at the grain boundaries. Microstructure of the thermo-mechanically affected zone（TMAZ） on advancing side consisted of highly deformed grains, and small deformation on retreating side. When the rotating speed was 300 r·min-1 and the welding speed was 100 r·min-1 or the rotating speed was 600 r·min-1 and the welding speed was 300 r·min-1, the good weld was achieved, and the tensile strength of the joint reached 465 MPa and 464 MPa, about 70% of the ultimate strength of the base metal. The fracture analysis show that there were lots of low mesh dimples, the fracture mode of the joint was ductile/brittle mixed fracture. The micro-hardness of the top surface of the FSW joint was higher than that of the transversal section, and the micro hardness of the weld nugget zone presented an ascending trend form bottom to top.
出处
《理化检验（物理分册）》
CAS
2013年第8期516-521,537,共7页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
基金
国防基金资助项目(KZ101302117)
