The effects of several cold spray process parameters on deposition efficiency and bonding quality of Al-6061 powder on the same material were investigated. Single particles were deposited at different particle impact velocities, nozzle-orientations, and nozzle travel speeds. Thick multilayer deposits were prepared to evaluate the effects of substrate surface finish and nozzle-orientation on deposition efficiency and bonding strength. Microstructural evaluation was performed on both deposited single particles and multilayer thick deposits by using optical microscopy, SEM, and TEM. It was confirmed that bonding occurs in peripheral regions of the splats, while only partial bonding develops at the polar region even at high impact velocities. Further, there is a critical spray angle below which no deposition takes place. This critical spray angle depends on nozzle travel speed and the duration of spray. A new method for substrate surface preparation was proposed by spraying at angles below the critical spray angle with the same powder prior to coating. Using low angle spraying as a surface preparation strategy provides a bonding strength of 54 MPa as compared to 22 MPa obtained for grit blasted substrates. Spray angle also affects deposition efficiency, porosity, and microstructure. Reducing the spray angle from 90° to 30° results in decreasing the deposition efficiency from 48 to 16%, increasing the porosity from 0.84 to 1.36%, and changing the microstructure from tightly bonded microstructure into columnar microstructure with porosity developed at inter-columnar regions.

研究了几种冷喷涂工艺参数对Al-6061粉末在同一材料上的沉积效率和结合质量的影响。单个粒子以不同的粒子冲击速度、喷嘴方向和喷嘴行进速度沉积。制备厚的多层沉积物以评估基板表面光洁度和喷嘴方向对沉积效率和粘合强度的影响。通过使用光学显微镜、SEM 和 TEM 对沉积的单个颗粒和多层厚沉积物进行微观结构评估。已经证实，键合发生在splats的外围区域，而即使在高冲击速度下，也只有部分键合发生在极性区域。此外，存在一个临界喷射角，低于该喷射角不会发生沉积。这个临界喷射角取决于喷嘴行进速度和喷射持续时间。提出了一种基材表面处理的新方法，即在涂层前以低于临界喷射角的角度喷涂相同的粉末。使用低角度喷涂作为表面处理策略可提供 54 MPa 的粘合强度，而喷砂基材则为 22 MPa。喷射角度也影响沉积效率、孔隙率和微观结构。将喷射角度从 90° 减小到 30° 导致沉积效率从 48% 降低到 16%，孔隙率从 0.84% 增加到 1.36%，并且微观结构从紧密结合的微观结构变为柱状微观结构，孔隙在柱间区域形成. 提出了一种基材表面处理的新方法，即在涂层前以低于临界喷射角的角度喷涂相同的粉末。使用低角度喷涂作为表面处理策略可提供 54 MPa 的粘合强度，而喷砂基材则为 22 MPa。喷射角度也影响沉积效率、孔隙率和微观结构。将喷射角度从 90° 减小到 30° 导致沉积效率从 48% 降低到 16%，孔隙率从 0.84% 增加到 1.36%，并且微观结构从紧密结合的微观结构变为柱状微观结构，孔隙在柱间区域形成. 提出了一种基材表面处理的新方法，即在涂层前以低于临界喷射角的角度喷涂相同的粉末。使用低角度喷涂作为表面处理策略可提供 54 MPa 的粘合强度，而喷砂基材则为 22 MPa。喷射角度也影响沉积效率、孔隙率和微观结构。将喷射角度从 90° 减小到 30° 导致沉积效率从 48% 降低到 16%，孔隙率从 0.84% 增加到 1.36%，并且微观结构从紧密结合的微观结构变为柱状微观结构，孔隙在柱间区域形成. 使用低角度喷涂作为表面处理策略可提供 54 MPa 的粘合强度，而喷砂基材则为 22 MPa。喷射角度也影响沉积效率、孔隙率和微观结构。将喷射角度从 90° 减小到 30° 导致沉积效率从 48% 降低到 16%，孔隙率从 0.84% 增加到 1.36%，并且微观结构从紧密结合的微观结构变为柱状微观结构，孔隙在柱间区域形成. 使用低角度喷涂作为表面处理策略可提供 54 MPa 的粘合强度，而喷砂基材则为 22 MPa。喷射角度也影响沉积效率、孔隙率和微观结构。将喷射角度从 90° 减小到 30° 导致沉积效率从 48% 降低到 16%，孔隙率从 0.84% 增加到 1.36%，并且微观结构从紧密结合的微观结构变为柱状微观结构，孔隙在柱间区域形成.