6061/AlSi12异种材料搅拌摩擦焊接头的组织与力学性能

Microstructure and Mechanical Properties of Friction Stir Welding Joints of 6061/AlSi12 Dissimilar Materials

对异种材料6061铝合金和Al Si12合金进行搅拌摩擦焊接试验,探究了6061/AlSi12异种材料搅拌摩擦焊接接头的组织与不同焊接速度对力学性能影响。结果表明:经拌摩擦焊接后,焊核区域由于受到搅拌针强烈的搅拌作用和摩擦作用,受到较高温度的热循环,使得6061晶粒发生再结晶,晶粒细化,块状Si发生缩颈、熔断并粒化,弥散分布在基体上,从而提高接头强度;当焊接速度为400 mm/min时,接头的抗拉强度达到最大175.93 MPa,是6061母材的70%,是Al Si12母材的90%;接头焊缝断面的横向微观硬度分布呈现"阶跃"式,当焊接速度为200 mm/min时,焊核区域的硬度最大。

The friction stir welding(FSW) welding experiments of 6061 aluminum alloy and Al Si12 alloy of dissimilar materials were carried out, and the effect of microstructure and welding speed of 6061/AlSi12 dissimilar material on the mechanical properties of FSW joint was investigated. The results show that after friction welding, the nugget area is subjected to high temperature thermal cycling due to the strong stirring and friction action of the stir needle, which results in recrystallization of 6061 grains, refinement of grain size and necking melting and granulating of block Si dispersed on the matrix, thus increasing the strength of the joints. When the welding speed is 400 mm/min, the tensile strength reaches the maximum of 175.93 MPA, which is 70% of 6061 base metal and 90% of Al Si12 base metal. The transverse microhardness distribution of weld section of the joint shows a "step" pattern. When the welding speed is 200 mm/min, the hardness of the nugget region is the largest.