Mn18Cr18N钢室温拉压循环加载力学行为和微观组织演变机理  

Mechanical behavior and microstructure evolution mechanism on Mn18Cr18N steel under tension-compression cycle loading at room temperature

作　　者：李飞[1,2] 张华煜 陈慧琴[1,2] Li Fei;Zhang Huayu;Chen Huiqin(School of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Shanxi Heavy Casting and Forging Engineering Technology Research Centre,Taiyuan 030024,China;School of Applied Science,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学材料科学与工程学院,山西太原030024 [2]山西省大型铸锻件工程技术研究中心,山西太原030024 [3]太原科技大学应用科学学院,山西太原030024

出　　处：《锻压技术》2023年第8期231-237,共7页Forging & Stamping Technology

基　　金：山西省基础研究计划青年项目(202203021222197);山西省高等学校科技创新项目(2021L326);太原科技大学博士科研启动基金资助项目(20212012)。

摘　　要：通过室温拉压循环加载试验,研究了Mn18Cr18N钢在±0.005~±0.10应变幅范围内的循环加载力学行为和微观组织演变。采用光学显微镜和透射电子显微镜观察了Mn18Cr18N钢包括金相组织、位错形态以及形变孪晶等亚结构在内的微观组织演变。研究结果表明,Mn18Cr18N钢在拉压循环加载中,循环力学特性和应变幅有关,随着循环应变幅的增大,Mn18Cr18N钢的循环应力幅呈现增大趋势。在应变幅为±0.10时,Mn18Cr18N钢经过1个周期循环加载后,流变应力为988.1 MPa,为0.2%初始屈服强度的1.6倍,这说明采用大应变幅循环加载提高了Mn18Cr18N钢的累积塑性应变,从而显著提高了强度。在较低应变幅(±0.005~±0.01)条件下,Mn18Cr18N钢的变形主要以平面滑移为主,位错重排和其他滑移系的激活是造成Mn18Cr18N钢循环软化的主要原因。应变幅较大时,高位错增殖使基体内应力升高,局部区域滑移困难,孪生机制被激活,Mn18Cr18N钢总体上呈现循环强化特性。The mechanical behavior and microstructure evolution of Mn18Cr18N steel under cycle loading in the strain amplitude range of±0.005-±0.10 were studied by room temperature tension-compression cycle loading tests.The microstructure evolution of Mn18Cr18N steel,including metallographic structure,dislocation morphology,deformation twins and other substructures,were observed by optical microscope and transimision electron microscope.The research results show that the cyclic mechanical properties of Mn18Cr18N steel are related to the strain amplitudes in the tension-compression cycle loading.With the increasing of cyclic strain amplitude,the cyclic stress amplitude of Mn18Cr18N steel shows an increasing trend.When the strain amplitude is±0.10,the rheological stress of Mn18Cr18N steel is 988.1 MPa after one cycle loading,which is 1.6 times of the 0.2%initial yield strength.The research indicates that the cumulative plastic strain of Mn18Cr18N steel is increased by the cycle loading with large strain amplitude to significantly improve the strength.At a lower strain amplitude(±0.005-±0.01),the deformation of Mn18Cr18N steel is mainly plane slip,and the dislocation rearrangement and the activation of other slip systems are the main reasons for the cycle softening of Mn18Cr18N steel.When the strain amplitude is larger,the proliferation of high dislocation increases the internal stress of the matrix,the local area slips difficultly,the twinning mechanism is activated,and Mn18Cr18N steel generally exhibits cycle strengthening characteristics.

关 键 词：Mn18Cr18N钢 拉压循环加载 力学行为 微观组织演变 应变幅 

分 类 号：TG316[金属学及工艺—金属压力加工]