热处理对GH4169激光焊接头组织性能的影响

针对2 mm厚的GH4169镍基合金板材进行激光对焊,研究热处理对GH4169激光焊接头组织和性能的影响。采用线切割方法制备激光焊接头试样,对热处理和非热处理激光焊接头进行拉伸实验、硬度测定、OM分析、SEM分析、EDS分析和XRD相分析。实验结果表明:热处理后接头抗拉强度为1372 MPa,延伸率为14%,焊缝平均硬度为473HV;较未热处理接头强度提高52%,延伸率降低71%,硬度提高69%。OM、SEM、EDS和XRD分析表明:对GH4169激光焊接头热处理能细化焊缝晶粒,改善枝晶形态,消除残余应力,析出δ相、γ′相和γ″相,使得焊接接头硬度和强度有所提高。

Effect of heat treatment on microstructure and properties of GH4169 laser welded joint

Laser butt welding was carried out on 2 mm-thick plates of GH4169 superalloy.Welded joint samples were cut by Wire Electrical Discharge Machining(WEDM).Half of the welded joint samples were standard heat treated and the others were not,and the hardness and tensile properties of the welded joints were evaluated.Results show that the tensile strength of the welded joints after heat treatment was 1372 MPa,the elongation was 14%,and the average weld hardness was 473 HV.Compared with non-heat treated welded joints,the tensile strength of the heat treated welded joints increased by 52%,elongation reduced by 71%,and hardness increased by 69%.OM,SEM,EDS,and XRD analyses show that heat treatment refined the laser welded joint grain,improved the dendrite morphology,eliminated the residual stress,and especially precipitatedδphase,γ′phase andγ″phase,which improved the hardness and strength of the welded joints.