High-rotation-speed friction stir welding (HRS-FSW) can effectively reduce welding load and has a great application prospect in the field of in-situ fabrication and repair. FSW of 6061-T4 aluminum alloy plate was performed using 1000−6000 rpm rotation speeds in this study, and a detailed investigation on the characteristic and mechanism of the nugget zone (NZ) performance was conducted from aspects of experiment and simulation. The results indicate that the HRS-FSW causes the area with higher temperature and strain to transfer from the shoulder-affected zone to the pin-affected zone and the material flow to be enhanced on the retreating side of weld, leading to the improvements in the size and symmetry of the NZ. Increase of rotation speed to higher values favors the grain growth and phase dissolution and simultaneously tends to weaken the effect of plastic strain on further increase in dislocation density. The grain size is found to dominate the NZ hardness evolution with rotation speed. The evolution of NZ hardness roughly presents a Hall-Petch relationship with the grain size.

高转速搅拌摩擦焊（HRS-FSW）可有效降低焊接负荷，在现场制作和维修领域具有广阔的应用前景。在本研究中，使用1000-6000 rpm的转速对6061-T4铝合金板进行FSW，并从实验和仿真的角度对块金区（NZ）性能的特征和机理进行了详细的研究。结果表明，HRS-FSW导致温度和应变较高的区域从肩部影响区转移到销轴影响区，并且在焊缝后退侧的材料流动得到增强，从而改善了新西兰的大小和对称性。将转速提高到更高的值有利于晶粒的生长和相的溶解，同时趋于削弱塑性应变对位错密度进一步增加的影响。发现晶粒大小决定了NZ硬度随转速的变化。NZ硬度的变化大致呈现出与晶粒尺寸的Hall-Petch关系。