Friction stir–assisted incremental sheet forming (FS-ISF) of aluminum alloy enables increased formability, solute precipitation strengthening, and stable microstructure with fine grains by dynamic recrystallization. However, higher rotating speed may destroy the surface quality of the forming part since process parameters have contradictory effects on macroscopic and microscopic results. To solve this dilemma, microstructure characteristics and macroscopic differences in FS-ISF experiments combining rotating speed and step-down increment on AA2024 and AA6061 are revealed. And the effects of parameter combinations on key macro- and micro performance indicators including forming depth, surface roughness, mechanical properties, solute precipitation, and grain sizes are comprehensively analyzed to propose an optimum process window for achieving better macro-micro indicators at the same time by both raising rotating speed (S≥4500RPM) and decreasing step-down increment (∆d≤0.4mm). Finally, the applicability of the proposed process window for preferable microstructure distributions and improved macroscopic properties is proved by supplementary FS-ISF experiments.

铝合金的摩擦搅拌辅助渐进片材成形（FS-ISF）能够通过动态重结晶提高可成形性，溶质沉淀增强和具有细晶粒的稳定显微组织。但是，较高的转速可能会破坏成形零件的表面质量，因为工艺参数对宏观和微观结果有矛盾的影响。为了解决这个难题，在FS-ISF实验中揭示了AA2024和AA6061的转速和降压增量相结合的微观结构特征和宏观差异。以及参数组合对关键的宏观和微观性能指标的影响，包括成形深度，表面粗糙度，机械性能，溶质沉淀，小号≥ 4500RPM）和减小降压增量（Δ d ≤ 0.4mm间距）。最后，通过补充的FS-ISF实验证明了所提出的工艺窗口对于最佳的微观结构分布和改善的宏观性能的适用性。