金属拉伸试验引起的应变速率脆性  

Strain rate embrittlement of metal induced by tensile test

作　　者：于鸿垚[1] 刘珍君[1] 王凯[1] 徐庭栋[1] 

机构地区：[1]钢铁研究总院高温材料研究所

出　　处：《钢铁研究学报》2015年第3期45-53,共9页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(51171050)

摘　　要：弹性变形会引起杂质元素在晶界处浓度的改变,这将导致晶界脆性的发生。基于多晶金属弹性变形的微观理论,研究了拉伸试验弹性变形过程中金属材料的脆性,探讨了应变速率对材料力学性能的影响,提出了临界应变速率和应变速率脆性的概念。应变速率脆性是一种应变速率改变引起的晶界脆性,在临界应变速率下,应变速率脆性达到极大值。随着测试温度的降低,临界应变速率向低应变速率移动,这是应变速率脆性的一个基本特征。临界应变速率的存在及应变速率脆性的特征已从大量文献的试验结果得到证实。Contents of impurity elements at grain boundary can change during elastic deformation,which induces grain boundary embrittlement（GBE）.Based on the microscopic elastic deformation theory of polycrystalline metal,embrittlement of metallic materials during elastic deformation of tensile test was analyzed.The effect of strain rate on the mechanical properties of tested materials was discussed.The new conceptions,critical strain rate（CSR）and strain rate embrittlement（SRE）were proposed.SRE is a kind of GBE induced by change of strain rate.SRE will get a maximum at CSR.The characteristic of SRE is that CSR will always move to lower strain rate with test temperature decreasing.The existence of CSR and the characteristic of SRE were verified by a lot of experimental results of steels and alloys from literatures.

关 键 词：拉伸试验 晶界脆性 偏聚 断面收缩率 

分 类 号：TG115.52[金属学及工艺—物理冶金]