To reduce the thermal stress at the clad layer and further reduce the crack generation in the laser cladding process, a method of controlling the cracks at the clad layer by changing the laser energy density is proposed. Comparative thermal–mechanical coupling finite element analysis was performed on the uniform rectangular and convex shape beam spot cladding processes on plasma-sprayed MCrAlY coating through the numerical simulation method based on the ANSYS software. Results show that rapid heating and cooling characteristics, which are typical in laser processing, are manifested in the cladding process using a uniform rectangular spot, whereas a convex shape spot can exert preheating and slow cooling effects to a certain extent, thereby reducing the temperature gradient of the cladding and non-cladding zones. In addition, on the precondition of equivalent cladding effect, the thermal stress at the clad layer is also low, enabling the effective mitigation of the cracking tendency of the clad layer. Relative to the laser beam-shaped diffractive optical element special for design and manufacturing, superposing two uniform rectangular spots with different sizes and energy densities is a simpler and more effective method of obtaining a convex shape spot.

为了降低熔覆层的热应力，进一步减少激光熔覆过程中裂纹的产生，提出了一种通过改变激光能量密度来控制熔覆层裂纹的方法。通过基于ANSYS软件的数值模拟方法，对等离子喷涂MCrAlY涂层上均匀矩形和凸形束斑熔覆工艺进行了比较热-机械耦合有限元分析。结果表明，采用均匀矩形光斑的熔覆过程表现出激光加工中典型的快速加热和冷却特性，而凸形光斑可以在一定程度上发挥预热和缓冷作用，从而降低温度梯度。包层区和非包层区。此外，在等效熔覆效果的前提下，熔覆层处的热应力也较低，能够有效缓解熔覆层的开裂倾向。相对于专门设计制造的激光束形衍射光学元件，将两个大小和能量密度不同的均匀矩形光斑叠加在一起，是获得凸形光斑的更简单有效的方法。