脉冲激光刻蚀作用下冷喷涂沉积过程数值模拟

脉冲激光会烧蚀材料形成表面微纳结构,研究该刻蚀作用下的冷喷涂沉积过程,以提高表面修复质量与效率。首先,结合脉冲激光作用过程与实验观测结果建立了单/多粒子与基板的沉积模型;其次,运用热-结构耦合算法对存在表面微纳结构时的粒子/基板碰撞过程开展数值模拟,研究了脉冲激光刻蚀作用对冷喷涂材料沉积过程的影响;最后,分析了脉冲激光-冷喷涂复合修复过程中材料的沉积机理。结果表明,刻蚀作用形成的微纳结构使得粒子与基板的温度分布更加均匀,形变更加复杂,特别是碰撞中心区域的形变得到显著提升;且粒子碰撞在基板表面微纳结构的波峰处时应变、温升最大,波谷处时最小;脉冲激光-冷喷涂的沉积机理为塑性射流处的机械-物理结合与激光熔化区的冶金焊合。

Numerical simulation of cold spray deposition process under pulsed laser etching

The pulsed laser ablates the material to form a surface micro-nano structure. In order to enhance the quality and efficiency of surface repair, the cold spray deposition process after pulse laser etching pretreatment was studied. Firstly, based on the pulsed laser action process and experimental observation results, simulation models between single/multiple particles and substrate were established. Secondly, thermal-structure coupling algorithm is used to carry out numerical simulation of the collision process between particle and substrate with surface micro-nano structures, and the effect of pulsed laser etching on the deposition process of cold sprayed materials is studied. Finally, the material deposition mechanism during the pulse laser assisted cold spray repair process was analyzed. The results show that the micro-nano structures formed by etching makes the temperature distribution in the collision area more uniform, and the deformation is more complicated, especially the deformation of the collision center area is significantly improved. When the collision position is the peak of the micro-nano structure, the strain and temperature rise are the largest, and the valley is the smallest. The deposition mechanism of pulse laser assisted cold spray is mechanical-physical bonding at plastic jet area and metallurgical welding in laser melting zone.smallest. The deposition mechanism of pulse laser assisted cold spray is mechanical-physical bonding at plastic jet area and metallurgical welding in laser melting zone.