残余应力直接影响修复件性能及尺寸稳定性, 为降低修复应力, 进行了低能量输入工艺参数组合及不同扫描路径的激光沉积修复GH4169合金试验研究。通过正交试验, 研究了激光功率、扫描速度、送粉速度对沉积层熔高、熔宽、熔深以及热影响区宽度等特征尺寸的影响规律, 采用低功率参数组合以及长边扫描路径与短边扫描路径, 进行盲槽损伤试样的激光沉积修复, 并检测分析了基体残余应力的分布情况。试验表明, 相比1 400 W高功率参数, 采用600 W低功率参数的修复试样残余应力明显减小, σx的平均降幅为48 MPa, 降低14.0%; σy的平均降幅为105 MPa, 降低37.8%; 与长边扫描修复相比, 短边扫描修复的残余应力略低, σx降低了25 MPa, 降低7.8%, σy降低了38 MPa, 降低18.0%。试验结果表明, 采用低功率参数组合和短边扫描路径有利于降低激光沉积修复GH4169合金的残余应力。

Residual stress affect the stability of property and size directly, aiming to reduce the residual stress in repairing process, low-power input process parameters combination and different scanning path in laser deposition repair GH4169 alloy were studied. By orthogonal test, the effect of weld height, weld width, weld depth and width of heat-affected zone under laser power, scanning speed and powder feeding rate have been investigated. Non-through groove damage specimen are repaired through adopting long edge scanning and short edge scanning path with matching low-power process parameters combination, and the residual stress distribution of substrate is analyzed. Experiments show that in contrast to high-power parameters with 1400 W, residual stress is reduced obviously comparing with low-power parameters of 600 W, the average residual stress reduction at x dimension was 48 MPa, which reduced by 14.0%, the average residual stress reduction at y dimension was 105 MPa, which reduced by 37.8%. Compared to the long edge scanning specimen, the residual stress of short edge scanning specimen was slightly decreased, the average residual stress reduction at x dimension was 25 MPa, which reduced by 7.8%, the average residual stress reduction at y dimension was 38 MPa, which reduced by 18.0%. The experimental results indicate that low-power process parameters combination and short edge scanning path are beneficial to reduce the residual stress of laser deposition repair GH4169 alloy.