Probing neck growth mechanisms and tensile properties of sintered multi-nanoparticle Al-Cu systems via MD simulation

Abstract

In the present work, a series of molecular dynamics simulations are conducted to figure out how sintering parameters would influence the atomic structure, sintering mechanisms, and elastoplastic properties of sintered Al-Cu nanoparticulate systems. For this purpose, first, utilizing the atomic potential energy diagrams, the suitable sintering temperatures for the introduced nanoparticles (NPs) have been calculated. NPs are then sintered at the temperatures of 410, 510, 600 and 680 K, and microstructural changes have been probed during the process. Finally, employing a uniaxial tensile test, the sintering temperature and holding time effects on the tensile behavior of the sintered products are studied in detail. Our simulation results indicate a strong correlation between the crystalline structure of the sintered NPs and the process temperature. It is also concluded that the main sintering mechanism at low-temperature conditions is dislocation slip, while at elevated temperatures, the sintering mechanism switches to diffusion-based phenomena. Moreover, it is revealed that increasing the sintering temperature from 410 to 680 K enhances the Young modulus of the samples monotonically, while the greatest yield strength is achieved at 600 K. Similar correlation is also found between the holding time and mechanical properties of the final product.