典型纳米单晶铝构件损伤破坏的原子模拟

ATOMISTIC SIMULATIONS FOR DAMAGE AND FAILURE OF TYPICAL NANOCRYSTALLINE ALUMINUM COMPONENTS

基于修正的镶嵌原子势函数描述原子间相互作用,建立纳米电机系统中两类典型铝构件——一维纳米单晶铝丝和二维纳米铝超薄膜受单向加载时损伤破坏过程和变形机制的原子模拟模型。通过分子动力学模拟得到两类纳米单晶铝构件的力学性能和变形机制及损伤初始化与累积过程,分析自由表面及原子间相互作用对纳米晶构件力学性能和变形机制的影响。研究结果表明,一维和二维纳米铝构件的拉伸破坏过程分别趋于宏观韧性和脆性,一维构件可承受变形更高;二者拉伸断裂强度分别可达11.142 GPa和11.84 GPa,远高于宏观铝构件,弹性模量分别为76.332 GPa和76.6 GPa,接近宏观铝构件。

Presented is an atomistic model for mechanical behavior and properties of two typical nanocrystalline Aluminum components, nanowire and nano thin film. With modified embedded atom method, the damage and failure process of Aluminum single crystal nano wire and thin film under uni-axial tension was investigated, and mechanical properties, deformation mechanism, damage initiation and evolution of nanocrystalline Aluminum components were then obtained. The effect of free surf. aces and atomic interaction on the mechanical properties and deformation mechanism was also analyzed. Simulation results show that the tensile failure process of nanowire and nanofilm is close to ductile and brittle respectively, and the critical tensile strain is much higher in the former. Tensile strength of Aluminum nanowire and nanofilm is much higher than that of macro components, revealing 11. 142 GPa and 11.84 GPa, but elastic modulus approaching macro components, is 76. 332 GPa and 76.6 GPa respectively.