基于稳定最大应变的冷喷涂粒子临界速度预测

Prediction of Critical Velocity in Cold Spraying Based on Numerically Calculated Steady Maximum Equivalent Plastic Strain

利用ABAQUS显式有限元分析软件,对冷喷涂铜粒子与铜基体的碰撞过程进行了欧拉法数值分析。结果表明,欧拉模型可有效模拟冷喷涂粒子碰撞变形行为,粒子撞击基体形貌的模拟结果与试验观察吻合较好。在不同碰撞速度下,最大等效塑性应变均会快速上升并达到各自稳定值,并且在290～400m/s内稳定等效应变最大值基本不变,但随着粒子速度增加,粒子扁平化程度、与基体结合面积与金属射流量均明显增加。最后,结合金属射流形貌与等效塑性应变稳定最大值的变化规律,提出了一种冷喷涂粒子临界速度预测的新方法,计算获得了20μm铜粒子冷喷涂临界速度约为290m/s。

An Eulerian method available in the ABAQUS software is used to simulate the impact process of cold sprayed copper particle on copper substrate. Results show that the simulated cross-sectional shapes after impact are quite comparable to the experiments, which indicates that the developed Eulerian method can effec- tively investigate the cold spraying process. A steady maximum equivalent plastic strain is found at various im- pact velocities and almost keeps constant at the impact velocity from 290 m/s to 400 m/s. The increasing im- pact velocity aggravates particle flattening and enlarges the jet formation from both the particle and substrate materials. After understanding the effect of impact velocity on the steady maximum PEEQ and the jet forma tion, an effective approach for predicting the critical velocity in cold spraying is proposed. The calculated criti- cal velocity achieving to jet formation is 290 m/s.