【摘要】 研究了高纯度Ｆｅ－０．０６％Ｃ－１．８０％Ｍｏ和Ｆｅ－０．１９％Ｃ－１．８１％Ｍｏ合金在５５０～８５０℃恒温时的贝氏体转变．结果表明，转变是完全的．两种合金分别在６００℃和５８５℃左右恒温时，转变会出现暂时停滞的现象，而后恢复并加快转变．两合金ＴＴＴ图均有一明显稳定区（Ｔｂ）．７５０℃恒温，形成铁素体和平行于奥氏体晶界的片状或杆状碳化物沉淀．７００－６００℃恒温在较高碳量和钼量形成少量的粒状（或节瘤状）贝氏体，７００℃恒温转变后期可观察到少量珠光体，Ｔｂ温度上下铁素体形貌明显不同，Ｔｂ以下的贝氏体铁素体为变异型，在晶界和晶内生成．更多还原

【Abstract】 The isothermal bainitic transformations at temperatures from 550℃ to 850℃ in high purity Fe 0.064%C 1.80%Mo and Fe 0.19%C 1.81%Mo alloys were studied. The overall transformation kinetics were determined by quantitative metallography. Contrary to conventional wisdom,austenite is completely transformed to bainite. The bainite transformation stops completely for a finite amount of time at 585℃ or 600℃ before resuming and going to completion. Both of these two steels show a significant bay in the TTT diagram for the initialization of transformation. There is a distinct change in ferrite morphology as the reaction temperature is decreased below the bay temperature ( T b). The transition with temperature from ferrite grain boundary allotriomorphs above T b to both intergranular and intragraular ferrite below T b is remarkably sharp. Especially at higher isothermal transformation tempertures, the decomposition of the austenite commences at grain boundaried. Interphase boundary Mo 2C precipitation in sheets was paralled to ferrite austenite boudried.更多还原