Magnesium-based alloys are appropriate materials for transportation applications owing to their high strength-to-weight ratio. However, the poor corrosion performance of Mg alloy limits its lifetime. In this study, the pure Al coating was deposited onto an AZ91D substrate by cold spraying, and then modified by friction stir-spot-processing. The interfacial microstructure and phase were studied in detail, and the effect of the intermetallic compounds on the microhardness and corrosion properties of the coatings was investigated. Results show that the sound and dense coatings were obtained after friction stir-spot-processing at 2400 and 2700 rpm. Al₁₂Mg₁₇ was found in the upper part of the 1/2 radius zone in the processed coating. The thin and thick IMCs were identified at the interface in the center and 1/2 radius areas, respectively. In the thick IMCs, mainly two types of multi-phase coexistence structures were observed. The four-phase coexistence structure dominated by Al₃Mg₂ revealed a higher microhardness than the three-phase coexistence structure dominated by Al₁₂Mg₁₇. In the processed coating, the upper part of the 1/2 radius zone containing Al₁₂Mg₁₇ exhibited a higher microhardness than the center zone. Moreover, the cold-sprayed Al coating provided more effective corrosion protection for the AZ91D substrate after FSSP.

镁基合金由于其高强度重量比是运输应用的合适材料。然而，镁合金较差的腐蚀性能限制了其使用寿命。在这项研究中，纯铝涂层通过冷喷涂沉积在 AZ91D 基材上，然后通过摩擦搅拌点处理进行改性。详细研究了界面微观结构和相，并研究了金属间化合物对涂层显微硬度和腐蚀性能的影响。结果表明，在2400和2700转/分的转速下进行摩擦搅拌点处理后获得了完好且致密的涂层。铝₁₂镁₁₇发现在加工涂层的 1/2 半径区域的上部。分别在中心和 1/2 半径区域的界面处识别出薄和厚的 IMC。在厚的 IMC 中，主要观察到两种类型的多相共存结构。以Al ₃ Mg ₂为主的四相共存结构比以Al ₁₂ Mg ₁₇为主的三相共存结构显示出更高的显微硬度。在处理后的涂层中，含有Al ₁₂ Mg ₁₇的1/2半径区域的上部表现出比中心区域更高的显微硬度。此外，冷喷涂铝涂层为 FSSP 后的 AZ91D 基材提供了更有效的腐蚀保护。