Mechanical properties are affected by coalescence mechanisms during sintering of metal powders: Case study of Al-Cu nanoparticles by molecular dynamics simulation

Abstract

In the present study, molecular dynamics simulation is utilized to explore atomic-scale evolution during the solid-state sintering of Al-Cu nanoparticles (NPs). Our main goal is to determine the ideal process parameters and desired mechanical properties of these metal NPs sintered at temperatures of 430, 510, 600, and 680 K. For this purpose, after examining the proper sintering temperature range using the atomic potential energy diagrams, we have probed the microstructural changes within the NPs during the process. Finally, employing uniaxial tensile tests, the temperature-dependent mechanical properties of the final products are studied. The results reveal a direct correlation between the temperature and the amount of stacking faults. It is also found that the process is mainly controlled by the dislocation slip at lower temperatures. In contrast, diffusion-based mechanisms play a vital role at higher temperatures. Moreover, it is concluded that rising the sintering temperature results in higher mechanical features.