Impacts of excess vacancies on order-domain growth in D03 Fe3Al intermetallic phase

Abstract

Properties of intermetallic compounds depend on the degree of order and the size of ordered domain (i.e., antiphase domain). Phase-field simulations can predict domain growth. However, precise prediction requires understanding of the ordering mobility. Herein, we examine the impact of excess vacancies on the ordered-domain growth in D0₃-Fe₃Al intermetallics using in-situ transmission electron microscopy (TEM). It was found that ordering mobility is correlated with excess vacancies introduced via rapid quenching from the disordered state. The similarity between the dependence of ordering mobility at 773 K on the quenching temperature and the dependence of equilibrium vacancy concentration on the temperature suggests that the diffusion for migration of domain boundary is dominated by the quenched-in excess vacancies. These findings advance fundamental understanding and enable control over the ordering in intermetallic fabrication through rapid solidification processes, such as powder bed fusion-type additive manufacturing.