K447A+GH4169惯性摩擦焊接头组织与高温力学性能

针对新型镍基铸造高温合金K447A和变形高温合金GH4169异种材料惯性摩擦焊工艺进行研究，对热处理后接头微观组织和高温力学性能进行试验分析，结果表明，K447A和GH4169惯性摩擦焊接头飞边成形良好，飞边根部无明显缺陷存在；接头焊缝区组织为完全再结晶组织，焊缝组织中的γ'和γ'相热处理后重新弥散析出，K447A侧仅形成了3 ~ 10 μm宽的再结晶区；通过接头高温力学性能试验，结果表明，接头高温拉伸和高温扭转性能断裂位置在K447A母材侧，400 ℃高周疲劳强度达到355 MPa. 在最大应力720 MPa，试验温度400 ℃条件下低周疲劳寿命均超过30 000次.

Microstructure and high temperature mechanical properties of inertia friction welding joint of K447A + GH4169

The dissimilar materials of Ni-base cast superalloy K447A and Ni-base wrought superalloy GH4169 were welded by Inertia Friction Welding (IFW). The microstructure and high temperature mechanical properties of the joints were studied after heat treatment. The results show that good flash can be formed after IFW and no clear defects were found at the root of the flash. Fine recrystallization zone was formed in the weld zone (WZ) and fine γ' phase and γ' phase were precipitated in the WZ after heat processing. The recrystallization zone width of the K447A side is between 3μm and 10μm. The high temperature tensile strength and torsional strength of GH4169 + K447A IFW joints were equal to K447A base metal. The high cycle fatigue strength of the joint is 355 MPa at the temperature of 400 °C. Under the condition of 400 °C and 720 MPa, the low cycle fatigue life of all the joint samples exceeded 30 000 times.