汽轮机汽蚀叶片YAG激光熔覆镍基合金研究

YAG laser clad Ni-based alloy on water-eroded steam turbine blades

用YAG激光器对表面汽蚀的2Cr13钢汽轮机叶片进行修复,采用同步送粉的方式进行自熔性Ni-Cr-B-Si合金粉末的激光熔覆。借助扫描电子显微镜(SEM)和能谱仪(EDS)对激光熔覆层进行组织及成分分析。研究结果表明,激光熔覆层硬度可达45～50 HRC,高于基底材料的硬度(35～40 HRC)。使用YAG固体激光对汽蚀叶片进行修复可以获得与母材冶金结合且无气孔、裂纹等缺陷的熔覆层,其组织主要是γ-Ni、Cr7C3、Ni2B、Ni3B以及少量的Cr2B和Cr3Si。

The water eroded steam turbine engine blades were repaired by YAG laser. The coatings were fabricated by laser cladding with direct injection of the Ni-Cr-B-Si powder into the molten pool. Laser clad coatings were characterized by scanning electron microscopy （SEM） and EDS. The results show that the laser cladding coatings have a higher hardness value （45 -50 HRC） compared with that of the substrate material 2Cr13 steel（35 -40 HRC）. The clad layer on the blades can be produced free of pores and cracks by YAG laser. The laser clad Ni-Cr-B-Si alloy coating is mainly a solid solution of γ-Ni with different nickel intermetallics, fundamentally NizB,Ni3 B together with the Chromium carbides Cr7C3 and with lesser proportions of CrzB and Cr3Si.