某型航空发动机高压涡轮工作叶片叶尖磨损后,采用激光熔覆技术进行修复,经X光探伤检查发现熔覆层与基体结合面上有纵向显微裂纹,其不合格率达到20%左右。通过基体材料成分分析、金相观察、扫描电镜、工业CT等手段分析裂纹产生原因,结果表明:裂纹为激光熔覆过程中应力过大产生的热裂纹,通过增加预热、调整激光出光模式等方式可有效降低裂纹故障率。控制措施实施后,继续跟踪检查24台叶片激光熔覆修复情况,其合格率达到99%以上。

After a certain type of aircraft engine high-pressure turbine blade tip was worn,laser cladding technology was used for repair.Through X-ray inspection,longitudinal micro cracks were found on the interface between the cladding layer and the substrate,with an unqualified rate of about 20%.By analyzing the composition of the matrix material,observing metallography,scanning electron microscopy,industrial CT and other methods,the causes of cracks were analyzed.The results showed that cracks were thermal cracks caused by excessive stress during laser cladding.Increasing preheating and adjusting the laser output mode can effectively reduce the failure rate of cracks.After the implementation of control measures,we continued to track and inspect the laser cladding repair of 24 blades,with a qualification rate of over 99%.