研究了高温合金K403基体上商用镍基自熔合金和自配无硼、硅元素镍基合金的激光同步送粉熔覆过程,分析了基体组织状态、熔覆层材料和熔覆工艺参数对熔覆层裂纹倾向的影响,探讨了激光熔覆技术强化和修复高温合金叶片的可行性.研究发现,激光熔覆时大多数裂纹是从基体侧形成后深入到熔覆层中,而基体组织中缩松等铸造缺陷及晶界低熔点共晶的存在是熔覆层开裂的重要原因.采用无硼、硅元素合金熔覆改善了结合区性能,与自熔合金相比,有助于改善熔覆层裂纹倾向.加入适量稀土氧化物有助于减少或消除裂纹.熔覆工艺参数对裂纹产生的影响较大,存在一个无裂纹参数选?穹段?研究证明,高温合金基体上熔覆无硼、硅元素合金更易于消除熔覆层裂纹,实现强化与修复更具优势.

This paper presents the research on coaxial powder feeding laser cladding of superalloy K403 with a commercial manual-mixed nickel based alloy and a manual-mixed nickel alloy free of boron and silicon. The effects of the substrate microstructure, clad materials and cladding parameters on the tendency to cracking were investigated. The feasibility on the strengthening and repairing of superalloy turbine blades by laser cladding was discussed. The results revealed that laser cladding of nickel based superalloy free of boron and silicon is good for eliminating cracks.