项目名称: 冲击加载下纳米多晶FCC金属塑性行为的原子尺度研究
项目编号: No.11202238
项目类型: 青年科学基金项目
立项/批准年度: 2013
项目学科: 数理科学和化学
项目作者: 马文
作者单位: 中国人民解放军国防科学技术大学
项目金额: 25万元
中文摘要: 金属材料的冲击压缩现象广泛发生于工业和国防科技领域,对此现象中塑性行为的深入认识具有重要的科学和工程意义。由于当前实验条件的限制,无法在原位从微观实验研究金属材料的塑性过程。纳米多晶金属由于包含了金属塑性变形的典型载体:位错和晶界,并且尺寸比较小而适合分子动力学模拟而被广泛用来研究面心立方(FCC)金属的微观塑形行为。本项目利用分子动力学方法直接从原子尺度出发模拟纳米多晶FCC金属的塑性变形过程,通过比较研究不同金属、不同晶界结构和不同晶粒大小在不同冲击加载条件下的塑形行为,独立地提取材料本征性质、晶界结构和晶粒大小等因素对微观塑形行为和宏观冲击响应的定性或半定量影响,从而系统研究晶界、位错等典型微结构在冲击加载过程中的微观演化规律,揭示塑性过程的内在物理力学行为,解释其如何影响宏观冲击响应。虽然本项目限于纳米多晶FCC金属,但得到认识有助与深入了解普通金属的塑形行为和宏观冲击响应。
中文关键词: 冲击波阵面;纳米多晶金属;晶界;塑性变形;分子动力学
英文摘要: The shock compressions of the metallic materials are widespread in the industrial and defense technology fields, and they are of great important in science and engineering to understand the plastic behaviors happened in these processes in depth. Due to the limitations of the current experimental conditions, the microscopic processes of plastic deformation of metallic materials can not be observed in situ. Because nanocrystalline (nc) metals contain the typical carriers of plastic deformation of metals: dislocation and grain boundary (GB), and because it's small size is suitable for molecular dynamics (MD) simulations, nc metals have been widely used to study the microscopic plastic behaviors of face-centered cubic (FCC) metals. In this project, the plastic deformation processes of nc FCC metals will be investigated from atomic scale directly using MD simulations. Through comparative studies on the plastic behaviors of different nc metals with different GB structures and GB sizes under varied shock loading conditions, qualitative or half-quantative effects of intrisinc material properties, GB structures and GB sizes on microscopic plastic behaviors and macroscopic shock responses can be obtained. Furthermore, the evolution pattern of typical microstructures (dislocations and GBs) during the process of plastic def
英文关键词: shock front;nanocrystalline metals;grain boundary;plastic deformation;molecular dynamic