FeNiCu合金中温度对微裂纹扩展影响的分子动力学研究

Molecular Dynamics of the Effect of Temperature on Microcrack Propagation in FeNiCu Alloys

张靖晨 杨帆 常筠袖 杜广煜 姜文全 陈昊楠

Jingchen ZHANG Fan YANG Junxiu CHANG Guangyu DU Wenquan JIANG Haonan CHEN

辽宁石油化工大学 机械工程学院, 辽宁 抚顺 113001 辽宁石油化工大学 石油天然气工程学院, 辽宁 抚顺 113001 东北大学 机械工程与自动化学院, 辽宁 沈阳 110819

School of Mechanical Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001，China College of Petroleum Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001，China School of Mechanical Engineering and Automation，Northeastern University，Shenyang Liaoning 110819，China

为了研究FeNiCu合金微裂纹在不同温度下扩展时发生的力学性能及微观机理变化，运用分子动力学方法，在300、500、700、900 K和1 100 K的温度下，对含有微裂纹和位错的FeNiCu合金模型进行了单轴拉伸模拟；使用可视化软件，对拉伸过程中FeNiCu合金的微观结构演变进行了分析；结合应力应变曲线以及能量变化曲线，着重分析了温度对FeNiCu合金微裂纹扩展微观机理的影响。结果表明，温度越高，合金内原子间距越大，微观结构越不稳定；随着温度的升高，合金的塑性得到提高，其微观缺陷在单轴加载下得到一定程度的愈合，可维持较为稳定的力学性能；当温度升高时，加强位错滑移，加剧位错的发射及运动，而位错塞积更容易形成微裂纹，使位错在滑移方向<110>多处塞积形成微裂纹扩展。

In order to study the mechanical properties and microscopic mechanism changes of microcrack propagation of FeNiCu alloy at different temperatures. In this paper, molecular dynamics methods were used to simulate uniaxial tensiles of FeNiCu alloy models containing microcracks and dislocations at 300, 500, 700, 900 K and 1 100 K, respectively. The microstructure evolution of FeNiCu alloys during tensile process was analyzed using Visualization software. Combined with the stress?strain curve and the energy change curve, the micro?mechanism effect of temperature on micro?crack propagation of FeNiCu alloy was emphatically analyzed. The results show that the higher the temperature in these five sets of temperatures, the greater the atomic spacing in the alloy and the more unstable the microstructure. However, the increase in temperature improves the plasticity of the alloy, so that the microscopic defects within it are healed to a certain extent under uniaxial loading, and the mechanical properties are maintained relatively stable. In addition, when the temperature rises, dissociative slip will be strengthened, which aggravates the emission and motion of the dislocation, and the dislocation product will be more likely to form microcracks, so that the dislocation <110> will form microcracks in multiple places in the slip direction.

国家重点研发计划项目(SQ2020YFB200353?4);辽宁省教育厅科学研究经费资助项目(L2019024)

10.12422/j.issn.1672-6952.2023.06.011