多晶Ti纳米柱塑性变形的分子动力学模拟研究

Plastic Deformation Mechanism of Polycrystalline Ti Nanopillars Based on Molecular Dynamics

利用分子动力学模拟研究多晶Ti纳米柱的力学行为和位错反应机制,比较分析不同变形温度和承载条件对多晶Ti纳米柱应力应变关系及其塑性变形行为的影响。模拟结果显示,随着温度升高,多晶Ti纳米柱屈服强度降低,且在不同温度下,屈服强度所对应的应变量未发生明显变化。在整个变形过程中,主要的位错类型为Other和1/3(1100)类型位错,随着温度升高,位错总长度减小。多晶Ti纳米柱压缩变形与拉伸变形应变响应不对称,拉伸屈服强度略高于压缩屈服强度,晶界缺陷在拉伸变形中响应更加明显。

The mechanical behavior and dislocation reaction mechanism of polycrystalline Tinanopillars were investigated by molecular dynamics simulation.The effects of different deformation temperatures and loading conditions on the stress-strain relationship and plastic deformation behavior of polycrystalline Ti nanopillars were compared and analyzed.The simulation results show that the yield strength of polycrystalline Ti nanopillars decreases as the temperature increases,and the amount of strain corresponding to the yield strength does not change at different temperatures.During the whole deformation process,the main dislocation types are Other and 1/3〈1100〉type dislocations,and the total length of dislocations decreases with the increase of temperature.The strain response of polycrystalline Ti nanopillars between compressive deformation and tensile deformation is asymmetric,the tensile yield strength is slightly higher than the tensile yield strength,and the grain boundary defects respond more obviously in the tensile deformation.