马氏体类型及其形成原因的探讨  

Exploration of martensite type and its formation

作　　者：马跃新[1] 吴煜[2] 曾德长[3] 谭玉华[2] 

机构地区：[1]中山火炬职业技术学院,中山广东528436 [2]湘潭大学材料科学与工程学院,湘潭湖南411105 [3]华南理工大学材料科学与工程学院,广州广东510006

出　　处：《材料热处理学报》2013年第4期155-161,共7页Transactions of Materials and Heat Treatment

基　　金：2008年广东省中山市科技攻关项目(20083A257)

摘　　要：采用光学显微镜、扫描电镜和透射电镜观测了9种钢的马氏体形貌。详细地论述了铁合金中,双色束状马氏体(低碳马氏体)、单色束状马氏体(中和高碳马氏体)、蝶状马氏体、透镜状马氏体、粗大薄片马氏体、枝干状马氏体等马氏体类型的形成原因。提出形核和生长激活能是决定马氏体各种形态出现的根源,其中界面能在形核激活能中所占的比例对低碳马氏体和枝干状马氏体的生成起着决定性的作用。认为共格相变产物的最小单元只可能是两种形态:板状和片状。各类马氏体的形核长大的方式也只有两种:1)小角差形核长大;2)孪晶关系形核长大。马氏体形核和长大的基本原则是增大同惯习面平行的界面,尽量减少其它界面。讨论了决定形核激活能和生长激活能的主要因素,对马氏体片状外形和内孪晶的形成提出了新见解;片状马氏体中具有内孪晶并不意味着滑移的临界分切应力超过了孪生临界分切应力;在马氏体中没有进行不均匀切变,产生孪生塑性形变。最后,认为:"马氏体切变理论"不符合马氏体相变的实际;将马氏体的片状外形和内孪晶视为马氏体高脆性的根源纯粹是"马氏体切变说"造成的人为偏见。The martensite morphology of nine kinds of commercial steels was observed by optical microscopy, scanning electron microscopy and transmission electron microscopy, The formation of different martensite, such as double contrast packet martensite （low carbon martensite ）, single contrast packet martensite（medium and high carbon martensite）, butterfly martensite, lens-martensite, coarse thin plate martensite and tree-trunk martensite in iron-base alloys were discussed in detail. It is concluded that nucleation and nucleus growth work are the source to determine the appearances of various martensite, among which the proportion of interface energy in the nucleation and nucleus growth work has a decisive function for the formation of the low carbon martensite and the trunk-like martensite, and the minimum unit of products of coherent transformation can only be two kinds of morphology： sheet -like in shape and plate-like in shape. The nucleation and nucleus growth modes of various martensite also have only two kinds：（ 1 ）The＂ small angle diff＂ nucleation and nucleus growth; （2）The ＂twinning relationship＂ nucleation and nucleus growth. The basic principle of the nucleation and nucleus growth of martensite is as far as possible to increase the interfaces parallel to habit plane and reduce other interfaces. The main deciding factor of the nucleation and nucleus growth work is discussed. New views were proposed for producing the plate-like appearance of martensite and forming internal twins. The plate martensites having internal twins does not mean that the critical resolved shear stress of slipping exceeds that of twinning. There isn＇ t any inhomogenized shear in the martensite to produce the twin＇s plastic deformation of martensite. It is argued that＂The martensite shear theories＂ doesn＇t conrrespond with the actual situation of martensite transformation. It is an artificial prejudice arised out of ＂the martensite shear says＂ that the high brittleness of martensite occurs due to t

关 键 词：马氏体 马氏体相变 马氏体形成机理 

分 类 号：TG111.5[金属学及工艺—物理冶金]