TRIP钢单双向应力状态下的材料行为  

Investigation on the material behaviors of TRIP steels under uniaxial and biaxial stress state

作　　者：林海[1] 李先超[2] 马金龙[2] 李洪洋[2] 

机构地区：[1]上海汽车集团股份有限公司乘用车公司制造工程部,上海201804 [2]北京理工大学材料学院,北京100081

出　　处：《塑性工程学报》2013年第4期27-32,共6页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51075034)

摘　　要：TRIP钢中残余奥氏体的马氏体相变是TRIP钢相变增塑的重要基础,与材料的宏观应力应变状态密切相关。为探索这一微观材料行为与宏观变形条件间的对应关系,该文对低碳Si-Mn TRIP600钢杯突变形顶部与过渡区的材料行为进行研究。研究结果表明,杯突过程中变形区顶部为等双拉平面应力状态,过渡区为单拉平面应力状态;TRIP钢的马氏体相变对应变条件非常敏感,随变形量的增加,无论变形区顶部还是过渡区的残余奥氏体体积分数,均呈近线性降低趋势,但随应变的增加则呈逐渐饱和趋势;与底部相比,顶部等双拉平面应力状态更利于残余奥氏体的马氏体相变,在近相同应变条件下,等双拉平面应力状态下的残余奥氏体含量明显低于单拉平面应力状态。Si-Mn TRIP600钢在6%应变条件下,等双拉平面应力状态与单拉平面应力状态的残余奥氏体含量相差约7%。The martensitic transformation of retained austenite in TRIP steels is the fundamental of TRIP steels phase transforma- tion plasticity, which depend on the macroscopic stress and strain condition greatly. To investigate the relationship between mi- croscopic material behaviors and macroscopic deformation conditions, low-carbon Si-Mn TRIP600 steel material behaviors of top and transitional section in cupping test was studied. It is shown that during cupping test, the stress state of the top section of the deformation area is equal biaxial stretching plane stress, meanwhile, the transitional section is uniaxial stretching plane stress. The martensitic transformation in TRIP steels was sensitive to strain condition, the retained austenite volume fraction in both top and transitional section shows a nearly linear decrease trend with the increasing of strain. But the trend of gradual saturation can also be found with the increasing of strain. Compared with the bottom, the equal biaxial stretching plane stress condition in the top section is beneficial to the martensitie transformation, and under a nearly same strain condition, the retained austenite volume fraction under biaxial stretching plane stress condition is lower than uniaxial stretching plane stress condition. For the the Si Mn TRIP600 steel of this paper, under 6% strain condition, there is 7% difference between the retained austenite volume fraction of equal biaxial stretching plane stress condition and uniaxial stretching Dlane stress condition.

关 键 词：TRIP钢 杯突实验 残余奥氏体 马氏体相变 双向拉伸 

分 类 号：TG115.50[金属学及工艺—物理冶金]