We present an experimentally validated computational model for microstructural evolution in the cold spray additive manufacturing process of Al6061 alloy coating. The microstructural characteristics are determined with a dislocation density-based model that is shown to be applicable to cold spray modeling and is implemented in a Eulerian finite element framework to predict microstructural evolution for both single and multiple particle cold spray deposition. A comparison of the numerical and experimental results from Scanning Electron Microscope (SEM), Electron Backscatter Diffraction (EBSD) and Kernel Average Mis-orientation (KAM) analyses, reveals the evolution of cell size and mis-orientation resulting in grain refinement at the particle–substrate and particle–particle interfaces. Although there is a large plastic deformation due to high speed impact, the dislocation density in the particle decreases with distance from the impacting interface and this feature is observed in both the simulation results and the experimental characterization data. The validated model can be leveraged to predict microstructural evolution under different process conditions including spray angle, pre-heat temperature, and impact velocity.

我们提出了一种经过实验验证的Al6061合金涂层冷喷涂添加剂制造过程中微观组织演变的计算模型。微观结构特征由基于位错密度的模型确定，该模型显示适用于冷喷涂建模，并在欧拉有限元框架中实施以预测单颗粒和多颗粒冷喷涂沉积的微观结构演变。扫描电子显微镜（SEM），电子背向散射衍射（EBSD）和核平均取向错误（KAM）分析的数值和实验结果的比较，揭示了晶胞尺寸的演变和取向错误，从而导致了颗粒的晶粒细化-基质和颗粒-颗粒界面。尽管由于高速撞击会产生较大的塑性变形，但粒子中的位错密度会随着与撞击界面的距离而减小，并且在模拟结果和实验表征数据中都可以观察到此特征。经过验证的模型可用于预测不同工艺条件（包括喷雾角度，预热温度和冲击速度）下的微观结构演变。