This project aims to encode inbuilt 3D microstructural gradients into high-performance alloys by harnessing inherent heterogeneities of additive manufacturing. The new physical metallurgy knowledge concerns advancements in the understanding of the interrelationship between tuneable characteristics of powder bed fusion processes and phase transformation pathways. Expected outcomes are 3D printing routes to unlock new property—performance spaces for aerospace and defence applications. Commercial benefits are opportunities to domestically source and manufacture engineering parts with reduced dependency on international trade. Environmental and societal benefits include reduced emissions due to superior mechanical design and workforce training.