摘要
应用分子动力学方法模拟纳米晶铁在单向拉伸载荷作用下的力学性能与微观结构演化过程。结果表明，平均晶粒尺寸在2．82～8．47nm范围内，纳米晶铁的弹性模量和试样的相对密度呈线性关系，抗拉强度随晶粒尺寸的减小而减小。显示出反常的Hall—Pethch效应。纳米晶铁试样在塑性变形过程中，出现了晶粒旋转、晶界运动、晶界滑移和位错运动，在局部区域出现了从bcc到fcc和hcp结构的应力诱导相变，这与纳米晶fcc金属不同。
The mechanical properties and evolution of the microstructure of nano-grain iron under uniaxial tensile deformation are simulated by using the method of the molecular dynamics. The results show that within a range of 2.82-8.47nm in grain size, Young＇s modulus has a linear relationship with the relative density of the samples and tensile strength is increased with the increase of the grain size, a reverse Hall-Petch effect is presented. The grain rotating, grain boundary sliding and movement and dislocation migration occur during the plastic deformation and the stress induced phase transition from bcc to fcc and hcp appear in the local sample. This is different from the nano-grain fcc metals.
出处
《有色金属》
CSCD
北大核心
2008年第1期32-35,40,共5页
Nonferrous Metals
基金
国家自然科学基金资助项目(90405016)
关键词
金属材料
纳米晶铁
分子动力学
相变
力学性能
metal material
nano-grain iron
molecular dynamics
phase transition
mechanical property
