不同焊速下7×××系铝合金FSW接头组织及性能研究

Investigation on Microstructure and Properties of FSW Joint of 7××× Series Aluminum Alloy at Different Welding Speed

采用金相、扫描、显微硬度测试、拉伸等试验手段,研究了转速1 600 r/min,焊速600 mm/min、900 mm/min以及1 200 mm/min下7046-T6铝合金薄板搅拌摩擦焊接头的组织与性能。试验结果表明:焊核区的晶粒细小均匀,600 mm/min焊速下焊核区的晶粒较为粗大。受热循环的作用,热影响区晶粒呈现一定程度的粗化长大。热机影响区和焊核区的过渡区的最低硬度为108 HV。当焊接速度为900 mm/min时,焊接效果较好,焊接接头的强度为350.3 MPa,达到母材抗拉强度500 MPa的70.1%。

The microstructure and properties of friction stir welded joint of 7046-T6 alloy sheet at 1600 rpm,600 mm/min,900 mm/min and 1200 mm/min were researched by means of metallography,scanning,microhardness test and tensile test. The results show that the grains in the nugget zone are fine and uniform,the grain size of the nugget zone is larger than that of the other two at600 mm/min welding speed. And the grains in the heat affected zone coarsen and grow to a certain extent under the action of heat cycle. The minimum hardness of the transition zone of heat mechanical affected zone and nugget zone is 108 HV. When the welding speed is 900 mm/min,the welding effect appears better. The strength of the welded joint is 350.3 MPa,which reaches 70.1% of the base metal’s tensile strength of 500 MPa.