目的 研究超音速微粒沉积过程中,不同颗粒的沉积状态以及后续颗粒的夯实作用对涂层沉积的影响规律。 方法 采用显式非线性有限元软件 LS-DYNA 模拟单层颗粒与基体的碰撞,采用自动二维单面接触 ASS2D(Automatic 2-D single surface contact)求解接触过程,研究超音速微粒沉积中多颗粒沉积行为、后续颗粒碰撞对涂层成形的影响规律。 采用超音速微粒沉积技术在铝合金表面制备 Al-Si 涂层,通过扫描电子显微镜(SEM)分析涂层的表面/ 截面形貌,进而验证模型的可靠性。 结果 多颗粒沉积过程中,颗粒与颗粒之间相互嵌合,形成互锁效应,有利于提高涂层的结合强度。 后续颗粒对先沉积颗粒具有夯实作用,夯实作用使颗粒扁平化程度加大,同时使颗粒之间紧密结合,存在夯实作用的颗粒压缩率提高至 3 倍以上,有效避免了涂层孔隙和裂纹的形成。 通过观察所制备的 Al-Si 涂层的表面/ 截面形貌,证明模型具有可靠性。 结论 采用数值模拟方法探讨超音速微粒沉积多颗粒在基体上的变形行为,可为超音速微粒沉积的应用提供理论依据。

Objective To study deformation behavior of supersonic multi-particles and analyze laws of the effect of deposition state of different particles and continuous particle compaction on coating formation. Methods The dominant non-linear finite element software LS-DYNA was used to simulate the impact of single particles and matrix, the automatic 2-D single surface contact was used to calculate the impact process so as to study the multi-particle deposition behavior and the influence pattern of continuous particle collision. In addition, the scanning electron microscopy (SEM) was used to analyze morphologies of the Al-Si coatings prepared by supersonic particles deposition (SPD) process on Al alloy to verify the reliability of the model. Results In the impinging process, multi-particles showed interlocking and extrusion effects between particles and this phenomenon was favorable for increase of adhesive strength. Also, the temping effect of continuous particles on pre-deposited particle increased the flattening of the particles and made the compression ratio increased by as far as 3 times, meanwhile, the temping effect avoided the porosity and flaws during the deposition process. The observation of the surface / section morphology of the prepared Al-Si coating proved the reliability of the model. Conclusion Numerical simulation methods can be used to investigate deformation behavior of supersonic particles, and provide a theoretical basis for the application of supersonic particle deposition.