The weldability of the AA2024-T3 and AZ31 Mg alloys was investigated using the modified friction stir clinching-brazing (MFSC-B) and probe-less friction stir spot brazing (PFSSB) processes. A 50 µm thick Zn foil-interlayer was sandwiched between the dissimilar base materials for the welding processes. The mechanical, microstructure, and weld-fracture behaviors of all joints were studied and compared. Zn-rich interdiffusion-aided lamellar and blocky structures are found at the brazed region/zone of the AA2024-T3/Zn/AZ31 joint irrespective of the welding process due to the sole influence of heat input at the zone. The differential flow in the MFSC-B joint enforces significant inter-material mingling, better distribution of Zn, and more subgrains/dislocation density at the joint as compared to the PFSSB joint. The interlayer inhibited the creation of the β-Al₃Mg₂ phase while the γ-Al₁₂Mg₁₇ phase could not be prevented in the AA2024-T3/Zn/AZ31 joints due to tool-induced atomic collision and diffusion–reaction mechanisms. Improved tensile/shear failure load is found in the MFSC-B joint (4369 N) as related to their PFSSB counterpart (3018 N) due to improved material flow (intermixing), and intense dislocation density. The MFSC-B process is thus recommended for dissimilar joining of Mg and Al alloys.

AA2024-T3 和 AZ31 镁合金的可焊性采用改进的搅拌摩擦铆接钎焊 (MFSC-B) 和无探针搅拌摩擦点钎焊 (PFSSB) 工艺进行研究。50 µm 厚的锌箔夹层夹在不同的基材之间，用于焊接工艺。对所有接头的力学、微观结构和焊接断裂行为进行了研究和比较。在 AA2024-T3/Zn/AZ31 接头的钎焊区域/区域发现富锌相互扩散辅助的层状和块状结构，与焊接过程无关，这是由于该区域的热量输入的唯一影响。与 PFSSB 接头相比，MFSC-B 接头中的差异流动在接头处加强了显着的材料间混合、更好的锌分布和更多的亚晶粒/位错密度。由于工具引起的原子碰撞和扩散-反应机制，AA2024-T3/Zn/AZ31 接头中的₃ Mg ₂相而无法阻止γ-Al ₁₂ Mg ₁₇相。由于改进的材料流动（混合）和强烈的位错密度，MFSC-B 接头 (4369 N) 与 PFSSB 接头 (3018 N) 的拉伸/剪切破坏载荷有所改善。因此，建议将 MFSC-B 工艺用于 Mg 和 Al 合金的异种连接。