关于贝氏体铁素体形核的评述——兼复徐祖耀《评刘宗昌等“贝氏体……”一文》  

Comment on nucleation of bainite ferrite——Reply to the paper《Comment on the paper …… authored by LIU Zong-chang》authored by XU Zu-yao

作　　者：刘宗昌[1] 计云萍[1] 任慧平[1] 袁长军[1] 段宝玉[1] 

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《材料热处理学报》2013年第3期176-180,共5页Transactions of Materials and Heat Treatment

基　　金：内蒙古自治区科技引导计划项目(20071911)

摘　　要：贝氏体铁素体在晶界形核的新观察验证了形核的一般规律。依据试验观察,理论计算得贝氏体临界晶核尺寸和形核功为:a*=16.7 nm;b*=25 nm,ΔG*=270 J.mol-1,此值合理。奥氏体中贫碳区的存在是普遍事实,试验也测得贝氏体相变孕育期内形成了贫碳区;不能将Spinodal分解与奥氏体中形成贫碳区和富碳区混为一谈。涨落是相变的契机,在孕育期内奥氏体中必由于涨落而形成贫碳区。阐述了非协同热激活跃迁形核机制。大量TTT图分析和实测均表明贝氏体铁素体形核-长大不可能以扩散方式进行。It is argued that the new experimental observation of the bainite ferrite nucleation at grain boundary validates the general rule of nucleation. According to the experimental observation, the calculated values of the critical crystal nucleus dimension and the critical nucleus nucleation energy of bainite ferrite, which are as follows, a＂ = 16. 7 nm, b＊ =25 nm andAG＊ =270 J.mol-~ , are reasonable. The existence of carbon depleted region in austenite is a common fact. Furthermore, the formation of the carbon depleted region in the incubation period of bainite transformation has been measured. Spinodal decomposition and the formation of rich and poor carbon zones in austenite cannot be confused with each other. The incoordinate heat activation transition mechanism of bainite transformation is set forth. The analysis of TTT diagrams and the actually measured results show that the nucleation and growth of bainite ferrlte cannot be by means of diffusion.

关 键 词：贝氏体铁素体 晶界形核 扩散 切变 热激活跃迁 

分 类 号：TG142.11[一般工业技术—材料科学与工程]