In this work, friction stir processing (FSP) was applied to the high-strength and high-melting-point Ni–Fe-based superalloy (HT700) for the first time with negligible wear of the stir tool. Different rotation rates were chosen to investigate the effect of heat input on microstructure and tensile properties at different temperatures of friction stir processed Ni–Fe-based superalloy. The results showed that with increasing rotation rate, the percentage of high-angle grain boundaries and twin boundaries gradually decreased whereas the grain size initially increased and then remained almost constant; the difference in tensile properties of FSP samples with rotation rates of 500–700 rpm was small attributing to their similar grain size, but the maximum strength was achieved in the FSP sample with a rotation rate of 400 rpm and traverse speed of 50 mm/min due to its finest grain size. More importantly, we found that the yield strength of all FSP samples tensioned at 700 °C was enhanced clearly resulting from the reprecipitation of γ′ phase. In addition, the grain refinement mechanism of HT700 alloy during FSP was proved to be continuous dynamic recrystallization and the specific refinement process was given.

在这项工作中，搅拌摩擦处理（FSP）首次应用于高强度和高熔点的镍铁基高温合金（HT700），搅拌工具的磨损可忽略不计。选择不同的转速来研究热输入对搅拌摩擦加工的 Ni-Fe 基高温合金在不同温度下的微观结构和拉伸性能的影响。结果表明，随着转速的增加，大角度晶界和孪晶界的百分比逐渐降低，而晶粒尺寸先增大后几乎保持不变；转速为 500-700 rpm 的 FSP 样品的拉伸性能差异很小，因为它们的晶粒尺寸相似，但 FSP 样品的最大强度在 400 rpm 的转速和 50 mm/min 的横向速度下实现，因为其粒度最细。更重要的是，我们发现在 700°C 下拉伸的所有 FSP 样品的屈服强度明显提高，这是由于 γ' 相的再沉淀造成的。此外，证明了HT700合金在FSP过程中的晶粒细化机制为连续动态再结晶，并给出了具体的细化过程。