气体温度对冷喷涂Ni粒子结合与变形行为的影响

利用SEM对冷喷涂工艺中不同气体温度下Ni粒子碰撞Cu合金基板后的结合及变形形貌进行了表征.结果表明,随着气体温度的升高,粒子扁平率呈渐缓趋势增加,射流面积增大,粒子的结合率提高.变形粒子内存在剪切失稳薄层、强塑性变形区和低塑性变形区等3个变形程度不同的区域.粒子与基板的结合质量主要受剪切失稳薄层控制,而变形后粒子的形状主要受塑性变形区控制.证实了绝热剪切失稳是Ni粒子与Cu合金基板结合的主要机制.

EFFECT OF GAS TEMPERATURE ON DEFORMATION AND DEPOSITION BEHAVIORS OF COLD-SPRAYED Ni PARTICLES

The bonding and deformation behavior of cold-sprayed Ni particles impacted on Cu alloy substrate at different gas temperatures were characterized by SEM. The results show that particle flattening ratio increases with the increase of gas temperature, but the increment rate decreases at higher gas temperature, moreover, the ratio of bond increases due to the increment of material jet area at the interface. It is also found that a typical Ni particle impacted on the substrate consists of shear instability thin layer, and severe and low plastic deformation regions. The quality of the particle/substrate bonding is mainly governed by the shear instability thin layer, while the shape of the deposited particle is mainly governed by the plastic deformation regions. It is confirmed that the successful bonding between Ni particle and Cu alloy substrate can be attributed to the adiabatic shear instability mechanism.