残余奥氏体增强低碳Q-P-T钢塑性的新效应  

A NEW EFFECT OF RETAINED AUSTENITE ON DUCTILITY ENHANCEMENT OF LOW CARBON Q-P-T STEEL

作　　者：王颖[1] 张柯[1] 郭正洪[1] 陈乃录[1] 戎咏华[1] 

机构地区：[1]上海交通大学材料科学与工程学院,上海200240

出　　处：《金属学报》2012年第6期641-648,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金重点项目51031001和国家自然科学基金面上项目51071101资助~~

摘　　要：低碳Fe-0.25C-1.48Mn-1.20Si-1.51Ni-0.05Nb(质量分数,%)钢通过新型Q-P-T工艺处理后获得高的抗拉强度和良好延伸率的综合性能.对该低碳Q-P-T钢在拉伸过程中残余奥氏体含量的XRD测定和形变孪晶马氏体的TEM观测,证明了相变诱发塑性(TRIP)效应的存在.基于形变过程中马氏体和残余奥氏体中的平均位错密度测定和TEM的观察,验证了在中碳钢中最新发现的残余奥氏体吸收位错(DARA)新效应在低碳钢中同样存在,由此提出了DARA效应产生的条件,阐明了残余奥氏体增强高强度钢塑性的机制.A low carbon Fe-0.25C-1.48Mn-1.20Si-1.51Ni-0.05Nb（mass fraction,%） steel exhibits the combination of high tensile strength and good elongation after treated by a novel quenchingpartitioning -tempering（Q-P-T） process.The variation in volume fraction of retained austenite in this steel with strain is measured by XRD,and the deformed twin-type martensite plates are also observed by TEM,from which the transformation induced plasticity（TRIP） effect in this steel is confirmed. Based on the measurement of average dislocation densities in both martensite and retained austenite combined with TEM observation,the effect of dislocation absorption by retained austenite（DARA） is found in the low carbon steel,similar to that in the medium carbon steel proposed recently,from which the generation conditions of DARA effect is proposed,and the mechanism of retained austenite on ductility enhancement of high strength steel is clarified.

关 键 词：高强度钢 Q-P-T工艺 平均位错密度 残余奥氏体 残余奥氏体吸收位错(DARA)效应 

分 类 号：TG142[一般工业技术—材料科学与工程]