Ti-adsorption induced strain release in promoting α-Al nucleation at TiB2 - Al interfaces

An ab-initio study of (0001) TiB2/Al-Ti interface reveals the effect of Ti-adsorption on enhancement of α-Al nucleation. Ti-adsorbed TiB2/Al atomistic interfacial models were established to simulate Ti-terminated TiB2/Al and B-terminated TiB2/Al interfaces. It is found that formation of Al3Ti intermediate layer initiates dislocations at the interfaces. Such an effect promotes the release of interfacial strain and free-growth of α-Al, thus enhancing the nucleation potency. Ti-adsorption plays a critical role in promoting strain release at the (0001) TiB2/Al-Ti interface, which also ensures the lattice-mismatch superiority of Al3Ti structure. It is proposed that the effect of solute-adsorption on the interfacial strain-release and lattice-mismatch shall be both considered when designing the substrate-solute pairs to enhance nucleation potency.