Abstract According to the downhole temperature filed, the mechanical behavior of TWIP steel for expansion tube was studied in the temperature range from 25°C to 300°C. Meanwhile, the phase and microstructure changes before and after deformation were investigated by X-ray diffractometer (XRD), optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that yield strength, tensile strength and elongation decrease with temperature increasing. The TWIP steel is single-phase of austenite before and after deformation. Analysis on the microstructure shows that the deformation twins gradually decrease with increasing temperature. The deformation process cannot benefit from the deformation twins, which is responsible for the decreased ductility. In addition, due to the increased temperature, the stacking fault energy becomes high enough to restrain twinning, thus dislocation glide becomes the main deformation mechanism.

中文翻译：

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变形温度对膨胀管用TWIP钢力学性能和显微组织的影响

摘要 根据井下温度场，研究了膨胀管用TWIP钢在25℃～300℃温度范围内的力学行为。同时，通过X射线衍射仪（XRD）、光学显微镜（OM）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了变形前后的物相和微观结构变化。结果表明，屈服强度、拉伸强度和伸长率随温度升高而降低。TWIP钢是变形前后的单相奥氏体。微观组织分析表明，随着温度的升高，变形孪晶逐渐减少。变形过程不能受益于变形孪晶，这是导致延展性降低的原因。此外，由于气温升高，