再论钢和β铜基合金中贝氏体相变形核机制  

Re-discussion on the mechanism of bainite nucleation in steels and β copper base alloys

作　　者：康沫狂[1] 朱明[1] 

机构地区：[1]西北工业大学材料学院,陕西西安710072

出　　处：《材料热处理学报》2007年第1期42-52,共11页Transactions of Materials and Heat Treatment

摘　　要：在试验用钢和β铜基合金固溶后等温或时效时,贝氏体孕育期是母相中溶质原子向晶体缺陷处和〈001〉晶向上扩散偏聚(形成贫、富溶质原子小区)的过程,即渐变(量变)阶段,为贝氏体形核做准备。当贫溶质小区贫化到以等温或时效温度作为Ms点的成分时,该小区即能进行马氏体样贝氏体切变形核,为突变(质变)阶段。孕育期也是一个受溶质原子扩散控制的过程。贝氏体形核是由过饱和的贝氏体和原始母相间溶质原子浓度差而产生的驱动力驱动。初期贝氏体有马氏体性质,是过饱和的。The bainite incubation period, during isothermally holding or aging in testing steels and β copper base alloys after solution treatment, is a process, in which, due to solute atoms diffusion and segregation at the crystal defects and at〈001〉crystal directions in the parent phase, distinct regions of solute enrichment and solute depletion are formed. This is a gradual （quantitative） change step and also provides the bainitc nucleation. When the Ms temperature at＇the solute depleted regions due to continual depletion, is equal to the isothermally holding temperature or aging temperature, bainite can nucleate at these depleted regions through shear mechanism of the martensitic manner. This is a sudden （quality） change step. The period is also a process controlled by the solute atoms diffusion in the parent phase.The driving force for bainite nucleation is produced by the difference on the solute atomic concentration between saturated bainite and original phase. Primary bainite should be provided with martensite characteristics and also super-saturated with the solute atoms.

关 键 词：贝氏体 孕育期 切变形核 相变基元 类Spinodal分解 

分 类 号：TG151.2[金属学及工艺—热处理]