摘要
通过在CMT4105试验机上进行准静态拉伸试验,在Hopkinson拉杆试验机上进行动态拉伸试验。在常温下,对DP1200冷轧双相钢进行应变速率为1×10^(-4) s^(-1)、1×10^(-3) s^(-1)、1×10^(-2) s^(-1)的准静态拉伸试验,以及应变速率为500 s-1、1 000 s-1、2 250 s-1的动态拉伸试验,并对拉伸断口进行形貌分析。结果表明:DP1200冷轧双相钢在准静态和动态变形条件下,随应变速率的增大,屈服强度s0.2从723 MPa增加到998 MPa,抗拉强度sb从1 205 MPa增加到1 515 MPa,断后伸长率从9.0%下降到7.7%,屈强比从0.60上升到0.66。准静态和动态拉伸的韧断口都呈现窝状,为韧性断口。应变速率为1×10^(-4) s^(-1)、1×10^(-3) s^(-1)、1×10^(-2)s^(-1)、500 s^(-1)、1 000 s^(-1)、2 250 s^(-1)断口韧窝平均尺寸分别为7.5μm、7.2μm、6.9μm、4.3μm、3.5μm和2.6μm,准静态拉伸不同应变速率下韧窝形貌变化不大,动态拉伸条件下随应变速率的增加断口韧窝变深。
Quasi static tensile experiments are done by CMT4105, and dynamic tensile experiments are done by Hopkinson tester. At room temperature, strain rate of the quasi static tensile experiments of DP1200 cold rolled steel are 1×10-4 s-1, 1×10-3 s-1, 1×10-2 s-1; strain rate of dynamic tensile experiments are 500 s-1, 1 000 s-1, 2 250 s-1. And fracture morphology analysis is done. The results reveals that with the increase of the strain rate on the conditions of quasi static tensile experiments and dynamic tensile experiments of the DP1200 cold rolled steel, the tensile strength increases from 1 205 MPa to 1 515 MPa, the yield strength increases from 723 MPa to 998 MPa and the yield strength ratio increases from 6.0 to 6.6, while the elongation decreases from 9.0% to 7.7%. Fracture morphology is toughening nest under quasi static tensile and dynamic tensile conditions. When the strain rates are 1×10-4 s-1,1×10-3s-1,1×10-2 s-1,500 s-1,1 000 s-1,2 250 s-1,the average sizes of fracture toughness are 7.5 μm, 7.2 μm, 6.9 μm, 4.3 μm, 3.5 μm and 2.6 μm. Fracture morphology changes little with the different strain rates under quasi static tensile condition, while the increasing strain rates make the toughening nest deeper under dynamic tensile conditions.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2016年第12期23-29,共7页
Journal of Mechanical Engineering
基金
国家高技术研究发展计划资助项目(863计划
2009AA03Z518)
关键词
高应变速率
双相钢
断口形貌
微观变形机理
板条马氏体
high strain rate
dual phase steel
fracture morphology
deformation microscopic mechanism
lath martensite
