Target-Sintering of Single-Phase Bulk Intermetallics via a Fast-Heating-Induced Rapid Interdiffusion Mechanism

Intermetallic compounds have attracted considerable attention as advanced structure materials with special properties. While a range of powder metallurgy methods have been developed to synthesize intermetallics, these approaches typically feature slow heating rates and therefore sluggish interdiffusion between the precursor powders, ending up with multiphase products with different metallic ratios. However, single-phase intermetallics offer more controllable properties for materials design yet remain difficult to achieve because of the synthetic limits. Herein, we report a target-sintering approach to synthesize a range of single-phase intermetallics, the stoichiometry of which is simply dictated by the chemical composition of the used precursors without any intermediate phase formation. This unique process is enabled by an ultrafast high-temperature sintering (UHS) method, which crucially offers fast temperature ramping (up to 103–104 °C/min vs. 101–102 °C/min in the conventional methods) to avoid phase impurity, as well as short sintering time to limit elemental loss. As a proof-of-concept demonstration, we synthesized, for the first time, a range of single-phase Ti–Al intermetallics, such as Ti3Al (phase fraction of 99.5%) and TiAl3 (phase fraction of 91.8%). This approach is promising for application to other intermetallic and alloy systems where target-sintering can be used to achieve a variety of single-phase materials.