纳米多晶体Ashby-Verrall超塑性模型的分子动力学模拟  

Molecular dynamics simulation of Ashby-Verrall superplasticity model for nano-crystal

作　　者：王为[1] 王长文[1] 张凯锋[1] 

机构地区：[1]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《塑性工程学报》2007年第2期35-38,49,共5页Journal of Plasticity Engineering

基　　金：国家自然科学基金(50375037)。

摘　　要：应用分子动力学方法以纳米晶铝为例模拟了纳米多晶体的Ashby-Verrall超塑性模型的变形过程。在OK～400K的温度下,大倾角的晶界较容易开动,符合Ashby-Verrall模型;但小倾角的晶界难于开动。温度升高至600K,纳米晶粒界面熔化,产生微液相,较小倾角的晶界也可随液相流动而开动;晶粒随着液相的流动旋转到有利于滑移的方向,完成Ashby-Verrall模型的变形。此时单个晶粒的变形机制符合Gifkins的“心部和表层”模犁。The deformation of Ashby-Verrall multi-crystal superplastic model is studied through molecular dynamics （MD） simulation using Al nano-crystal as an instance. Under 0K-400K, the grain boundaries with large tilt angle are easy to slide and the results agree well with Ashby-Verrall model; however, grain boundaries with small tilt angle are difficult to slide. When the simulating temperature is up to 600K, the interfaces melt and tiny liquid phases exist on them. Grain boundaries with small tilt angle can also start moving with the flowing of the liquid phase. At the same time, the grains rotate to the orientation is advantage to the deformation, and the Ashby-Verrall movement is accomplished. The deformation mechanism of single crystal in the model fits the Gifkins＇ ＂Center-Surface＂ model.

关 键 词：分子动力学 Ashby-Verrall超塑性模型 晶界 液相 

分 类 号：TB24[一般工业技术—工程设计测绘]