焊接参数对FGH96惯性摩擦焊接头组织和高温拉伸性能的影响

摘要

This study aims to evaluate the FGH96 superalloy joints fabricated by inertia friction welding (IFW) in different welding parameters, such as initial rotational speed and axial friction pressure, where the moment of inertia remained constant. The microstructure and the width of the weld nugget zone (WNZ) were analyzed, and tensile property of joints was examined. The effect of welding parameters on high temperature tensile property of FGH96 joints was investigated. The results show that the joint presents a significant microstructure change across the faying interface, characterized by the very small uniform equiaxed grains of WNZ, coarse and fine grain coexistence of the thermo-mechanically affected zone (TMAZ). As the rotation speed increases, the tensile property remains constant. However, with increasing friction pressure, they show a substantial increase.The change tendency of the width of WNZ with welding parameters is in agreement with that of tensile property, which is related to the weld heat input and the plastic flow of the material. The high temperature tensile specimens are fractured in the WNZ. This is related to the complete γ′-phase dissolution which softens the joint and decreases the joint tensile property. Therefore, the post-weld heat treatments are necessary for IFW FGH96 superalloy in order to further improve the joint properties.%固定转动惯量，使用不同的转速和摩擦压力，对FGH96高温合金进行惯性摩擦焊（IFW），分析接头组织和焊核区宽度，研究焊接参数对接头高温拉伸性能的影响。结果表明：接头焊核区（WNZ）为等轴细晶组织，热力影响区（TMAZ）粗、细晶共存，接头焊核区的细晶组织中基本没有γ′强化相；接头高温拉伸性能随转速变化较小，而随摩擦压力的增大而增加，且焊核区宽度随摩擦压力的变化规律与拉伸性能吻合，这与焊接热输入量、材料塑性流动有关；高温拉伸试件均断裂于焊核区，这是由于焊核区γ′强化相完全溶解于基体导致接头强度下降。