本文在干法室温常压状态下利用辊压振动磨制备了尺度在30~80纳米的铝纳米颗粒,并根据位错理论和点阵几何学,计算分析了铝颗粒在研磨过程中的尺度-结构演变规律,从能量的角度研究了铝颗粒在微尺度下的质能转换规律。研究表明,铝的晶体结构对于机械力的响应具有方向选择性。在研磨的初始阶段,材料的变形以应变为主,铝的晶粒细化与应变和位错几率的降低是同时发生的,应变和位错几率与晶粒尺度之间可以互相转换。在一定条件下,应变能可以得到释放,晶粒细化是在微应力大量释放、层错几率较低状况下得到的,即晶体颗粒的细化是应变能和层错能协同效应作用的结果。
Aluminum nanoparticles of 30-80nm were prepared by dry roller vibration milling at room temperature,the size and structural evolution of the aluminum particles in the milling process were analyzed by dislocation theory and lattice geometry.We found that the response of aluminum crystal structure to mechanical force is direction-selective.In the initial stage of milling,stacking faults governed the material deformation.However,grain size reducing is always accompanied by the reduction of micro-strain and dislocations in the material;it seems that they could be interchangeable each other.Under certain conditions,strain and dislocations could be released,resulting in grain refinement,but a certain milling period was required for the accumulation and release of the strain and stacking faults to get finer particles,the grain refinement is the two kinds of stress and the stacking fault mechanism for joint effects.
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