Laser cladding induces high tensile residual stress (RS), which can compromise the quality of a specimen. Therefore, it is critical to accurately predict the RS distribution in cladding and understand its formation mechanism. In this study, functionally graded material (FGM) layers were successfully deposited on the surface of a titanium alloy Ti6Al4V sheet by laser cladding technology. A corresponding thermo-mechanical coupling simulation model of the laser cladding process was developed to investigate the formation mechanism of RS in the laser cladding FGM layers. The results show that high tensile RS forms in cladding components. Subsequent cladding can effectively alleviate the RS in cladding components although the position of maximum RS remains unchanged. The measurement results of the longitudinal RS on the top and bottom surfaces of cladding components by the X-ray diffraction (XRD) method agreed with the simulation results, thereby proving the accuracy of the simulation. In addition, the formation mechanism of RS in the laser cladding FGM layers was revealed by discussing the individual impact of each material property on RS. It was indicated that the RS distribution in the laser cladding FGM layers was significantly affected by material properties (in particular, coefficient of thermal expansion and Young’s modulus), except for the temperature gradient induced by the laser cladding process.

激光熔覆会产生较高的拉伸残余应力（RS），这可能会损害样品的质量。因此，准确预测包层中的RS分布并了解其形成机理至关重要。在这项研究中，功能梯度材料（FGM）层已通过激光熔覆技术成功沉积在钛合金Ti6Al4V板材的表面上。建立了相应的激光熔覆过程热力耦合仿真模型，以研究激光熔覆FGM层中RS的形成机理。结果表明，高强度RS在覆层部件中形成。尽管最大RS的位置保持不变，但随后的包层可以有效缓解包层组件中的RS。X射线衍射（XRD）法在覆层组件上下表面的纵向RS的测量结果与模拟结果吻合，证明了模拟的准确性。此外，通过讨论每种材料性能对RS的单独影响，揭示了激光熔覆FGM层中RS的形成机理。结果表明，除激光熔覆过程引起的温度梯度外，激光熔覆FGM层中的RS分布受材料性能（特别是热膨胀系数和杨氏模量）的影响很大。通过讨论每种材料性能对RS的个体影响，揭示了激光熔覆FGM层中RS的形成机理。结果表明，除激光熔覆过程引起的温度梯度外，激光熔覆FGM层中的RS分布受材料性能（特别是热膨胀系数和杨氏模量）的影响很大。通过讨论每种材料性能对RS的个体影响，揭示了激光熔覆FGM层中RS的形成机理。结果表明，除激光熔覆过程引起的温度梯度外，激光熔覆FGM层中的RS分布受材料性能（特别是热膨胀系数和杨氏模量）的影响很大。