低Al含量Ti-Al纳米杆拉伸变形的分子动力学模拟

Molecular Dynamics Simulation of Tensile Deformation of Ti-Al Nano-Rod with Low Al Content

利用分子动力学模拟研究Ti-Al纳米杆的单向拉伸变形过程,比较分析不同拉伸速率、拉伸温度以及Al含量对Ti-Al应力-应变关系及其塑性变形行为的影响。模拟结果显示,在纳米尺度下,Ti-Al具有较高的屈服强度,且在断裂前显示出比宏观材料更好的塑性;在塑性变形中,启动(0001)面滑移系以及{10 12}<10 11>和{10 11}<10 12>孪晶是主要的变形机制;降低变形速率、提高变形温度有助于降低Ti-Al纳米杆的屈服强度,使塑性变形更容易进行,而增加Al含量则会降低Ti-Al的塑性变形能力,使Ti-Al更早发生颈缩断裂。

The uniaxial tensile deformation of Ti-Al nano-rod was studied by molecular dynamics simulation.The influence of strain rate,temperature and Al content on the stress-strain curve and the plastic deformation behavior were analyzed.The Ti-Al nano-rods have the higher yield strength and better ductility than macro material.The slipping of （0001） plane and the formation of { 10（1）2 }＜10（1）1＞ as well as {10（1）1}＜10（1）2＞ twinning are the dominant mechanism of the plastic deformation.The lower strain rate and higher deformation temperature decrease the yield strength and then benefit the plastic deformation.The increasing of Al content in Ti-Al reduces the ductility,which results in the earlier necking and cracking.