碰撞速度对冷喷涂粒子沉积行为影响的数值模拟研究

Numerical simulation of the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying

采用有限元数值模拟方法研究了冷喷涂过程中304不锈钢粒子的碰撞速度对IF钢基板的碰撞和沉积变形行为的影响。结果表明,当粒子速度高于一个在产生绝热失稳变形并发生沉积的临界速度时,粒子的扁平率、有效接触界面积均显著增加。粒子沉积过程中的剪切失稳行为是由撞击过程中产生的压力与摩擦力共同作用的结果。这个临界速度可以由数值模拟计算得到,用于优化多种材料的冷喷涂工艺参数。

The effects of the impact velocity of 304 stainless steel particles on IF steel substrate collision and sedimentary deformation in cold gas dynamic spraying（CGDS） were numerically simulated by means of a finite element analysis（FEA）.The results illustrated that when the particle impact velocity exceeds a critical value at which adiabatic shear instability of the particle starts to occur.The particles＇ flattening ratio and effective contact area will increase rapidly.The particle-substrate bonding and deposition mechanism can be attributed to such an adiabatic shear deformation induced by both the compressive force and the slide friction force of particles.The critical velocity can be predicted by numerical simulation,which is useful to optimize the CGDS processing parameters for various materials.