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采用金属催化的气相合成法制备高纯度单晶钨纳米线材料,采用分子动力学方法进行拉伸模拟计算,分析〈100〉、〈110〉、〈111〉3种典型晶向下单晶钨纳米线的拉伸应力-应变曲线及其微观变形结构,揭示晶向对单晶钨纳米线拉伸破坏机理的影响。结果表明:3种晶向均具有弹性、损伤、屈服、破坏等4个阶段,其中〈100〉晶向还具有独特的屈服后强化阶段和两次应力突降阶段。晶向对单晶钨纳米线弹性模量的影响较小,对抗拉强度、屈服强度和延展性的影响较大,主要取决于不同的原子表面能和主滑移面。计算得到的单晶钨纳米线的弹性模量值与实测结果吻合较好。
High-purity single crystal tungsten nanowire materials were prepared by metal-catalyzed gas-phase synthesis. The tensile simulation was carried out by using molecular dynamics method. Three typical crystal orientations of <100>, <110> and <111> Tensile stress-strain curves and microstructures of the nanowires are investigated to reveal the effect of crystal orientation on the tensile failure mechanism of single crystal tungsten nanowires. The results show that all of the three orientations have four stages of elasticity, damage, yielding and failure. The <100> orientation also has a unique post-yielding strengthening stage and two stress-relief stages. The effect of crystal orientation on the elastic modulus of single crystal tungsten nanowires is small, which has a great influence on the tensile strength, yield strength and ductility, and mainly depends on the different atomic surface energies and the main slip surface. The calculated elastic modulus of the single crystal tungsten nanowire is in good agreement with the measured data.