Synthesis of Ti2(In Al1-)C (x = 0–1) solid solutions with high-purity and their properties

Herein, high-purity Ti2(InxAl1-x)C (x = 0–1) solid solutions were successfully synthesized. The crystal structure and actual composition of solid solutions were confirmed using XRD, SEM, and TEM analyses, and their formation mechanism was revealed by thermal analysis. On the In-rich side (x ≥ 0.5), primary Ti2InC first formed and then acted as a crystalline seed for the subsequent solid solutions, resulting in a cluster-like morphology. The lattice constants of Ti2(InxAl1-x)C were found to well follow Vegard’s law. The examined properties of Ti2(InxAl1-x)C also greatly depended on their A-site compositions. Ti2AlC exhibited the highest hardness and elastic moduli, while the best corrosion resistance was achieved at Ti2InC, and all Ti2(InxAl1-x)C displayed active dissolution in 0.5 M HCl solution. Thus, adjusting the In/Al ratio at A-site can yield a desired set of performances, which provides a good example for regulating the performance of MAX phases via A-site solid solution strategy.