关于贝氏体形核和台阶机制的讨论——与徐祖耀院士等商榷  

Mechanism of Bainitic Nucleation and Ledge Growth——Discussion with Professor Hsu T Y(XU Zu-yao)

作　　者：康沫狂[1] 朱明[1] 

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《材料热处理学报》2005年第2期1-5,共5页Transactions of Materials and Heat Treatment

摘　　要：一些合金固溶化(或淬水)后在预贝氏体(孕育)期内等温淬火(或时效) ,既保持高温时形成的晶体缺陷,又产生新的晶体缺陷。母相中由于溶质原子扩散而在缺陷处发生偏聚,则形成贫 富溶质微区,即类拐点(spinodal like)分解。当贫溶质微区成分作为MS,其温度等于或高于等温淬火(或时效)温度时,贝氏体将以马氏体样切变形核,故贝氏体是在溶质原子扩散控制下切变形核。在TEM温台试验中未发现台阶生长机制,界面上巨型台阶是贝氏体增宽(厚)速度差异所致。During pre-bainitic (incubation) period of isothermal treatment (or aging) after solution treatment (or quenching), not only are the crystal defects formed at high temperature maintained, but new crystal defects can also be generated in some alloys. Due to the segregation of the solute atoms near defects through diffusion, this leads to the formation for the depleted/enriched solute regions in the parent phase, i.e., spinodal-like decomposition. It is proposed that when the MS temperature of the solute depleted regions is equal or higher than isothermal (or aged) temperature, the bainitic nucleation occurs within the solute depleted regions in the manner of martensitic shear. The ledge growth mechanism of bainite disappears in experiments. Superledge at the baintic boundary can be formed by the difference of the moving rate for the widening (thickening) of the bainitic lath.

关 键 词：预贝氏体期 扩散偏聚 贫/富溶质微区 巨型台阶 类拐点分解 

分 类 号：TG111.5[金属学及工艺—物理冶金]