基于分子动力学的α-SiO2晶体力学性能

Mechanical Properties of α-SiO2 Crystal Based on Molecular Dynamics

采用分子动力学方法,结合Tersoff势函数,模拟α-SiO2晶体在应变加载下的力学性能,并考察温度对α-SiO2力学性能的影响.结果表明:α-SiO2在常温加载过程中经历了弹性变形、塑性变形及断裂变形3个阶段,获得的屈服强度为22.6GPa,断裂强度为36GPa;在塑性变形阶段观察到α-SiO2从晶相向非晶转化的相变过程;随着温度的升高,α-SiO2的屈服强度和弹性模量逐渐降低;温度越高断裂应力和断裂应变越低,α-SiO2晶体在高温单轴加载下易出现断裂.

The mechanical properties of theα-SiO2 crystal under the loading of strain were simulated by using molecular dynamics method with Teroff potential function,and the effects of temperature on the mechanical properties ofα-SiO2 were studied.The results show that theα-SiO2 crystal undergoes three stages of elastic deformation,plastic deformation and fracture deformation in the process of uniaxial loading at room temperature,in which the yield strength is 22.6 GPa,the fracture strength is36 GPa.The transformation ofα-SiO2 from crystal phase to amorphous phase is observed during plastic deformation.The yield strength and elastic modulus ofα-SiO2 decrease gradually with the increase of temperature,and the higher temperature,the lower fracture stress and fracture strain,theα-SiO2 crystal is easy to fracture under high temperature uniaxial loading.