用 4 5k W高功率激光器对 Ni Cr Si B合金在送粉激光熔覆下裂纹形成的材料成分、熔覆工艺、微观组织等因素进行研究。实验表明 ,裂纹是由于熔覆层中大量的多种硬质相以及硬质相的不良分布形态所造成的高脆性 ,难以承受熔覆过程产生的较大拉应力所致。解决激光熔覆层裂纹问题的主要方向应是从工艺上降低熔覆过程的残余拉应力 ,同时从成分搭配和快速凝固特性上使得 Ni Cr Si B熔覆层微观组织中的硬质强化相细小均匀地弥散析出 ,保证熔覆层的高强度和高塑性 The composition of the crack, the cladding process and the microstructure of the NiCrBi alloy under the powder cladding laser cladding were studied with a 45kW high power laser. Experiments show that the crack is due to a large number of a variety of hard coatings in the cladding layer and the poor distribution of the hard phase caused by high brittleness, difficult to withstand the larger tensile stress caused by the cladding process. The main direction to solve the laser cladding crack problem is to reduce the residual tensile stress of the cladding process from the process. At the same time, the hard strengthening phase in the microstructure of the Ni Cr Si B cladding layer is made fine by the composition matching and the rapid solidification property Dispersed evenly dispersed, to ensure that the coating of high strength and high ductility