摘要
研究了304亚稳态奥氏体不锈钢在超低温和室温轧制变形过程中的宏、微观组织演变,变形引起的马氏体转变及其对合金性能的影响.结果表明,超低温轧制比室温轧制能更有效地加速马氏体转变,其中20%超低温轧制变形便可实现50%室温轧制变形下的马氏体转变量,且超低温轧制变形最终可实现完全的马氏体转变.同时,超低温轧制引起的马氏体转变在板厚方向上较均匀,显著优于室温轧制板材的板厚方向均匀性,有助于提高亚稳态奥氏体不锈钢板厚方向性能的均匀性.分析认为,亚稳态奥氏体不锈钢在超低温和室温轧制过程中具有不同的变形机理,前者主要以马氏体转变及其变形为主,后者以奥氏体变形为主.超低温轧制所获板材的硬度比室温轧制板材增长迅速,但随变形量增大位错密度差距缩小,最终导致两者硬度趋于一致.TEM表征结果表明,超低温和室温轧制过程中引起的马氏体与母相基体间的取向关系遵循K-S(Kurduumov-Sachs)关系.
Advanced material processing techniques have been successfully used to produce metals or alloys with submicro- or nano-sized grain structures with some possibly required harsh working environment that limits their industrial application. Cryogenic deformation might promote extensively severe deformation or distortion of metals or alloys （such as AI or alumininm alloys, Cu or copper alloys, Ti, Zr, etc.） so as to accumulate higher defor- mation energy （e.g., higher defect density） for the depression of the （dynamic） recovery, which will contribute to the microstructure refinement. Presently, the macro-/micro-structural evolution, the martensitic transformation as well as its effect on the mechanical property during the cryogenic and room temperature rolling of 304 metastable austenitic stainless steel were studied. It shows that the cryogenic rolling can effectively accelerate the martensitic transformation, e.g., after 20% cryogenic rolling the volume fraction of the transformed martensitic is equal to that after 50% room temperature rolling, and finally the cryogenic rolling can promote the complete martensitic trans- formation. Also the through-thickness uniformity of the martensitic transformation after cryogenic rolling is signifi- cantly better than that of the room temperature rolled one, which can help to improve the through-thickness perfor- mance uniformity. It is found that the deformation mechanisms are different for cryogenic and room temperature rolling metastable austenitic stainless steel： the martensitic transformation and its deformation occur in the former while austenitic deformation in the latter. The cryogenic rolling can quickly induce higher hardness than that of the room temperature rolled one, and the hardness tends to be equal finally because of the minimized dislocation densi- ty difference between these two rolled steels. TEM results indicate that the orientation relationship between the transformed martensite and the old austenite in the cryogenic and room temperature rolled sheets can still keep the K-S （Kurduumov-Sachs） relationship.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第8期945-955,共11页
Acta Metallurgica Sinica
基金
国家自然科学基金项目51401016
现代交通金属材料与加工技术北京实验室项目
新金属材料国家重点实验室基金项目2011Z-05资助~~
关键词
奥氏体不锈钢
超低温轧制
马氏体转变
X射线衍射
微观组织
austenitic stainless steel, cryogenic rolling, martensite transformation, XRD, microstructure
作者简介
史金涛，男，1988年生，博士生
