分子動(dòng)力學(xué)模擬
( 1. 湖南大學(xué)材料科學(xué)與工程學(xué)院， 長沙 410082;
2. 湖南大學(xué) 應(yīng)用物理系， 長沙 410082)
摘 要: 運(yùn)用分子動(dòng)力學(xué)技術(shù)， 結(jié)合分析型嵌入原子方法（AEAM）模擬計(jì)算了平均晶粒尺寸為2.09~5.23nm的納米多晶Ni的微觀結(jié)構(gòu)和力學(xué)性能。 從原子能量分布、 徑向分布函數(shù)(RDF)、 局域晶序結(jié)構(gòu)的角度分析了納米多晶Ni的晶界和晶粒結(jié)構(gòu)， 發(fā)現(xiàn)晶界部分所占的比例隨晶粒尺寸的減小明顯提高，結(jié)構(gòu)與普通微晶的相似， 納米晶體的結(jié)合能較普通晶體的低。 單向拉伸模擬結(jié)果表明： 納米多晶Ni的強(qiáng)度與晶粒尺寸之間出現(xiàn)反常Hall-Petch關(guān)系； 彈性模量的降低與納米尺度結(jié)構(gòu)特征相關(guān)。
關(guān)鍵字: 納米晶; 嵌入原子方法; 分子動(dòng)力學(xué); 力學(xué)性能
mechanical properties of nanocrystalline Ni
（ 1. School of Materials Science and Engineering,
Hunan University, Changsha 410082, China;
2. Department of Applied Physics, Hunan University, Changsha 410082, China）
Abstract: The nanostructures and mechanical properties of nanocrystalline Ni with average grain size ranging from 2.09nm to 5.23nm were simulated with analytic embedded-atom method(AEAM) and Molecular Dynamics(MD). The grain boundary(GB) and nanocrystalline grain structure were analyzed with radial distribution function(RDF), energy analysis and common neighbor analysis(CAN) methods. The results indicate that the fraction of GB increases with the grain size decreasing and the GB structure is similar to that of the conventional coarse crystalline. The binding energy of nanocrystalline is lower than that of conventional microcrystal. Stress—strain curves show the reverse Hall-Petch relation in the present simulations. The decrease of elastic modulus is dependent on the nanostructure.
Key words: nanocrystalline； embedded-atom method(EAM)； molecular dynamics； mechanical property
