【摘要】 用光学和透射电子显微镜观察了９ＳｉＣｒ钢在不同时间等温后的上贝氏体形态。探讨了上贝氏体的组织形态及对性能的影响。短时等温的上贝氏体具有特殊的形态，系由不含碳化物的单相小条状贝氏体铁素体组成。随着等温时间的延长，上贝氏体呈羽毛状。特殊形态的上贝氏体具有较高的强韧性更多还原

【Abstract】 The morphology of upper bainite in 9SiCr steel,which formed during austempering for several periods,was observed by optical microscope and TEM This paper deals with microstructure of the upper bainite and its effect on the mechanical properties The upper bainite emerge in short period austempering appeared with special morphology,which consists of monophase lath shape bainitic ferrite As prolonging of austempering time,upper bainite appeared with feather like structure The special upper upper bainite has better strength and toughness更多还原