采用扫描电镜、透射电镜、X射线衍射仪等对贝氏体等温转变后TRIP钢中的残余奥氏体及其稳定性进行了研究。结果表明，TRIP钢在贝氏体转变区400~440 ℃保温120~300 s，随着等温温度的升高和保温时间的延长，钢中残余奥氏体的含量不断增多，残余奥氏体碳含量呈降低趋势。TRIP钢中的残余奥氏体主要以薄膜状、粗大块状和细小粒状的形态存在。粗大块状的残余奥氏体稳定性最差，薄膜状次之，细小粒状最稳定。残余奥氏体的含量不足，或残余奥氏体的含量偏高造成碳含量的不足，都会导致TRIP钢综合成形性能的降低。此外，贝氏体等温处理时间过长，渗碳体的出现大大降低了残余奥氏体中的碳含量，从而降低了残余奥氏体的稳定性。

The retained austenite and its stability of transformation induced plasticity (TRIP) steel after isothermal bainitic transformation were investigated using SEM, TEM and XRD. The results showed that the amount of retained austenite is increased with increase of temperature or holding time of isothermal bainitic treatment in the range of 400440 ℃ and 120300 s respectively. At the same time the carbon content of retained austenite is decreased. It was found that the retained austenite is occurred in the forms of relative large particles, thin film and small globular particles. Obviously large retained austenite is unstable,thin film is more stable and fine globular particles are most stable.The combined formability of TRIP steel is deteriorated due to insufficient amount of retained austenite or reduced carbon content in retained austenite caused by excessive amount of retained austenite.Besides, the decrease of carbon content in retained austenite,caused by formation of cementite during extralong isothermal bainitic treatment makes stability of retained austenite reduced.