激光熔覆层结晶方向对覆层裂纹方向和开裂敏感性的影响

Effects of Crystallizing Orientation on Crack Direction andCracking Sensitivity in Laser Cladded Layers

通过调整激光熔覆铁基合金粉末的成分，发现熔覆层裂纹方向和开裂敏感性将随其成分的变化而变化。具体表现为：随着熔覆铁基合金粉末中Ｎｉ含量的增加，裂纹方向与激光扫描方向的夹角减小，直至裂纹消失。其原因是随Ｎｉ含量的变化，覆层搭接区结晶方向发生了改变。由此提出了通过控制结晶方向来达到减少熔覆层开裂敏感性的方法。

After adjusting components of the Fe-base alloy powder which is used to clad bylaser, we find that crack direction and cracking sensitivity in laser cladded layers change with composition of the cladded layers. The included angle between the crack direction and the laser scanning direction decreases as Ni content in the cladded layers is increased. When Ni content is increased to above 15wt-%, cracks disappear. The reason for these results is that the crystallizing orientation of the overlapping zone is changed with changing of the amount of Ni in the cladded layers. So we think that controlling the crystallizing orientation of laser cladded layers is an effective method to decrease the cracking sensitivity of laser cladded layers.