【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，转变中途出现暂时停滞的现象。而后恢复并加快转变。两合金等温等转（ＴＴＴ）图均有一明显稳定区（称为河湾或θｂ　），θｂ温度上下铁素体形貌明显不同。在７００～８００℃恒温时，碳化物平行于奥氏体晶粒边界沉淀。更多还原

【Abstract】 The isothermal bainitic transformations at temperatures from 550℃ to 850℃in high purity Fe-0.064%-1.80% Mo and Fe-0.19%C-1.81% Mo alloys are studied. Theoverall transformation kinetics were determined by quantitative metallography. Transmis-sion electron microscopy was employed to identify the carbides present and the fine-scalebainite morphology. Coatrary to conventional wisdom, austenite is completely transformedto bainite. This transformation occurs at least in these two steels, even at overall isothe-rmal transformation temperatures from 550℃ to 850℃. The bainite transformation stopscompletely for a finite amount of time at 585℃ or 600℃ before resuming and going tocompletion.Both of these two steels show a significant bay in the TTT diagram for theinitialization of transformation. There is a distinct change in ferrite morphology as thereaction temperature is decteased below the bay temperature (b). The transition withtemperature from ferrite grain boundary allotriomorphs above to both intergranular andintragranular ferrite below is remarkably sharp. Especially at higher isothermal trans-formation temperatures,the decomposition of the austenite commences at grain boundaried.Interphase boundary Mo2C precipitation in sheets was paralled to ferrite-austenite boun-daried.更多还原