Q-P-T制备高强钢的马氏体形成激光共聚焦观察和力学性能测定  

Laser confocal observation on the formation of martensite and test on the mechanical properties of steels treated by Q-P-T process

作　　者：常颖[1] 王存宇[2] 李晓东[1] 杨洁[3] 赵坤民[1] 胡平[1] 董瀚[2] 

机构地区：[1]大连理工大学汽车工程学院工业装备结构分析国家重点实验室,大连116024 [2]钢铁研究总院华东分院北京研发部,北京100081 [3]长城汽车股份有限公司技术中心,保定071000

出　　处：《中国科学：技术科学》2015年第7期714-720,共7页Scientia Sinica(Technologica)

基　　金：国家重点基础研究发展计划(批准号:2010CB630803);国家自然科学基金(批准号:51101036;51201093;11472072);辽宁省自然科学基金(批准号:2014028001)资助项目

摘　　要：作为第三代汽车钢的一种,淬火-碳配分-回火(Q-P-T)工艺制备的高强度钢显微组织由先形成马氏体、新鲜马氏体和残余奥氏体构成.本文利用激光共聚焦显微镜,观察了一次淬火时马氏体和未转变奥氏体分布的不均匀形成过程.在此基础上,进一步表征了在不均匀的基体中,Q-P-T工艺获得的马氏体具有多尺度的分布特征;同时,二次淬火获得的新鲜马氏体具有:1)更细的板条尺寸;2)在一个块状区域内具有相同的取向,可视为一个"packet";3)更高的力学性能.研究结果客观地展示了Q-P-T制备高强度钢的微观组织演化本质,为进一步改进Q-P-T工艺、提高性能提供了准确的理论依据.The advanced high strength steels（AHSS） for auto manufacturing have been developed to the 3rd generation. The typical one is steel treated by Q-P-T process, which consists of the prior martensite, fresh martensite and retained austenite. In this paper, the non-uniform distributive formation of martensite and untransformed austenite during the one-step quenching treatment was observed by laser scanning confocal microscope. For the Q-P-T process, the non-uniform distributions of untransformed austenite, prior martensite and segmented austenitic grains are the main reasons to form the multi-scale martenite. Moreover, the fresh martensite possesses three highlights, such as microstructure of finer laths, same orientation in a blocky area considered as a ＂packet＂ and higher mechanical properties. The research result of this paper reveals the microstructure evolution of Q-P-T treated steel, and provides the accurate theoretical basis for improving the Q-P-T process and the mechanical properties.

关 键 词：Q-P-T工艺 马氏体相变 激光共聚焦 残余奥氏体 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]