铝合金/不锈钢惯性摩擦焊接头的组织特性娃和力学性能研究

Microstructure characteristics and tensile strength of aluminum/stainless steel joint welded by inertia friction

摘要:

惯性摩擦焊是一种连接异种金属理想的焊接方法，铝合金/不锈钢采用惯性摩擦焊进行焊接，并详细研究了焊接接头的形貌、组织、界面成分和力学性能。结果表面，在惯性摩擦焊接头的界面处形成了很薄的金属间化合物（IMC）反应层，该反应层主要由Al、Fe元素组成，是富集Si元素的FeAl3相。惯性摩擦焊接头组织由焊核区、完全动态再结晶区、热机械影响区和热影响区组成。完全动态再结晶区的晶粒小于0.1μm，它的平均宽度为5μm。接头的显微硬度最大值出现在不锈钢侧的完全动态再结晶区，其值为395.8 HV。惯性摩擦焊中，初始转速对接头的拉伸性能有显著影响。当初始转速为1200rpm时，铝/钢惯性摩擦焊接头的最大拉伸强度为323MPa，达到铝合金母材强度的92%。

Abstract:

IFW method has the potential of being ideal technology to weld dissimilar materials, aluminum and stainless steel were welded by inertia friction, and the morphology, microstructure, interfacial composition and mechanical properties of Al/steel joints were investigated. Results showed that a thin IMC reaction layer was found at the welding interface in the joint, and the IMC was consisted of Al, Fe and high concentration Si. The microstructure of joint contained weld nugget zone, fully dynamic recrystallized zone, thermal mechanically affected zone and heat affected zone. The grain of fully dynamic recrystallized zone (FDRZ) was below 0.1 μm, and the average width of FDRZ in the joint was about 5 μm. The maximum hardness was in the FDRZ, and the maximum value was 395.8 HV in the joint. Tensile strength of joint was influenced by the rotational speed. When the rotational speed was 1100 rpm, the joint reached to the maximum tensile strength of 323 MPa. The high tensile strength reason should be related to the thickness of IMC at the weld interface.