Probing oscillatory pressure sintering mechanisms and mechanical properties of Ti6Al4V alloys via MD simulation

Abstract

This study investigates the coalescence kinetics of Ti6Al4V alloy under oscillatory pressure using a multi-particle model based on molecular dynamics. The results indicate that oscillatory pressure promotes a more uniform distribution of force on particles, resulting in Ti6Al4V samples with smaller grain sizes and more uniform phase distribution. The oscillatory pressure facilitates relative rotation and displacement between particles, aiding surface diffusion and particle bonding, thus accelerating the sintering process and enhancing the densification of Ti6Al4V alloy. Ti6Al4V samples processed with oscillatory pressure exhibit finer and more uniform microstructures, leading to an increased density of stronger grain boundaries and higher dislocation densities, thereby improving strength by impeding dislocation movement. Furthermore, the stronger grain boundaries and the presence of a greater amount of β-phase, distributed more uniformly in the Ti6Al4V samples processed with oscillatory pressure, enhance the alloy's plasticity. Overall, oscillatory pressure sintering significantly influences the mechanical properties of Ti6Al4V, suggesting the potential of the oscillatory pressure sintering method over conventional hot pressing in enhancing material performance.