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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择范围。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。
The laser simultaneous powder cladding process of commercial Ni-based self-fluxing alloy and boron-free and Si-based Ni-based alloy on superalloy K403 was studied. The microstructure and properties of the matrix were analyzed. The influence of cladding crack tendency, the feasibility of laser cladding technology to strengthen and repair the superalloy leaves. It is found that most of the cracks in the laser cladding are formed after the formation of the matrix and then penetrate into the cladding layer. The casting defects such as shrinkage and the low melting point eutectic in the matrix are the important reasons for the cracking of the cladding layer. Boron-free, silicon-based alloy cladding improves the performance of the bonding area, which is more beneficial than the self-fluxing alloy in improving the cracking tendency of the cladding layer. Adding appropriate amount of rare earth oxide helps to reduce or eliminate cracks. Cladding process parameters have a greater impact on the crack, there is a no crack parameter selection range. Studies have shown that the high temperature alloy matrix boron-free coating, silicon alloy is easier to eliminate the cladding layer crack, to strengthen and repair more advantages.