In this study, tensile behavior of Nb-containing 25Cr–20Ni austenitic stainless steels composed of coarse or fine grains has been investigated at temperatures ranging from room temperature to 900 °C. Results show that the tensile strength of fine-grained specimens decreases faster than that of coarse-grained specimens, as the test temperature increases from 600 °C to 800 °C. The rapidly decreasing tensile strength is attributed to the enhanced dynamic recovery and recrystallization, because additional slip systems are activated, and cross-slipping is accelerated during deformation in fine-grained specimens. After tensile testing at 700–900 °C, sigma phases are formed concurrently with dynamic recrystallization in fine-grained specimens. The precipitation of sigma phases is induced by simultaneous recrystallization as the diffusion of alloying elements is accelerated during the recrystallization process. Additionally, the minimum ductility is observed in coarse-grained specimens at 800 °C, which is caused by the formation of M₂₃C₆ precipitates at the grain boundaries.

在这项研究中，研究了在室温到900°C范围内的由粗晶粒或细晶粒组成的含Nb的25Cr-20Ni奥氏体不锈钢的拉伸行为。结果表明，随着测试温度从600°C升高到800°C，细颗粒试样的拉伸强度下降速度快于粗颗粒试样。拉伸强度的迅速下降归因于动态恢复和再结晶的增强，因为激活了附加的滑移系统，并且在细颗粒试样变形期间加速了交叉滑移。在700–900°C下进行拉伸测试后，在细晶粒试样中同时形成了σ相和动态重结晶。同时重结晶会导致σ相的析出，因为在重结晶过程中合金元素的扩散会加速。此外，在800°C的粗晶粒试样中观察到了最小的延展性，这是由于形成了M ₂₃ C ₆在晶界析出。