摘要
研究发现低层错能的亚稳材料低温拉伸存在一种新型的应力应变曲线．曲线表现为弹塑性失稳εｐｈ 、应力平台εＬ 及硬化指数ｎ 为不恒值的３ 个特点．试验结果表明：εｐｈ 、εＬ 随应变率增加而增大，硬化率ｄσ／ｄε与硬化指数ｎ 随应变量的增加呈抛物线型．弹塑性失稳及应力平台本质上不同于稳定态材料的上、下屈服及屈服平台，而是由相变引起的新的屈服机制，即弹塑性失稳是应变诱发马氏体转变的起始状态。
A new type of tensile curve, which exhibits elasto plastic instability(EPI),stress plateau and unconstant hardening exponent n, has been found at-196 ℃ in metastable material with low stacking fault energy(SFE).Experimental results show that EPI ε ph and stress plateau ε L increase with increasing strain rate, and the hardening rate and hardening exponent vary by paracurve with strain. The EPI and stress plateau are essentially different from upper and lower yield point and yield plateau in stable materials, that is ,the EPI results from strain induced martensite transformation, and the stress plateau from dynamic balance between phase transformation induced softening and hardening.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
1999年第10期64-67,共4页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金
关键词
拉伸曲线
弹塑性失稳
硬化指数
应力应变曲线
tensile curve
metastable material
elasto plastic instability
stress phateau
hadening exponent
