Monitoring micro-structural evolution during aluminum sintering and understanding the sintering mechanism of aluminum nanoparticles:A molecular dynamics study

作     者：Jun Jiang Pengwan Chen Weifu Sun Jun Jiang;Pengwan Chen;Weifu Sun

作者机构：State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation CenterChongqing401120China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2020年第54卷第22期

页      面：92-100页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 11802027 and 11521062) the State Key Laboratory of Explosion Science and Technology (Nos. JCRC1801, QNKT20-01) Beijing Institute of Technology Research Fund 

主　　题：Molecular dynamics simulation Aluminum nanoparticle Sintering Mechanical contact Microstructural evolution 

摘      要：In this work, molecular dynamics simulations have been performed to explore the structural evolution and underlying sintering mechanism of aluminum nanoparticles. The structural evolution during sintering was firstly monitored through radial distribution function and atomic migration, and the underlying sintering mechanism was further quantitatively characterized in terms of average displacement, mean squared distance(MSD), radius ratio(i.e., the ratio of the neck radius to the particle radius), shrinkage and radius of gyration, crystalline orientations, particle size, etc. Results show that the surface atoms of nanoparticles are more active than the internal atoms, favoring the mechanical rotation of nanoparticles during sintering. During the sintering process, average displacement, radius ratio and the shrinkage rate have undergone three stages with increasing the temperature:(1) a slow increase and subsequent abrupt hike after reaching the sintering temperature;(2) an almost plateau region over a wide span of temperature;(3) finally a sharp increase again after reaching the melting temperature. In contrast, MSD remains basically unchanged before melting, close to zero, followed by a sudden increase after melting temperature. Although the radius of gyration also experiences three stages, nonetheless it exhibits almost completely contrary trend. It has also been found that both sintering temperature and melting temperature demonstrate an almost linear increase with the increase of nanoparticle size ranging from4.0, 6.0, 8.0 to 10.0 nm in diameter. Finally, we also found that the particle direction has limited effect on neck growth during sintering.