Superior strength-ductility synergy of (TiC + Ti5Si3)/Ti composites with nacre-inspired architecture

Inspired by the ultrastrong and tough nacre structure, in this study, we prepared in-situ titanium (Ti) matrix composites (TMCs) containing laminated Ti, planarly aligned TiC and vertically distributed Ti5Si3 phases, which is close to the unique "brick-and-mortar" architecture of nacre. This concept was realized via electrophoretic depositing Si powders and graphene oxides (GOs) on pure Ti foils followed by spark plasma sintering. Results showed that dramatically higher yield strength (YS) of 829 MPa could be achieved in the composite, which is 178% higher than that of pure Ti counterpart while maintaining good plasticity of 8.1% in elongation. Compared with the laminated TiC/Ti composite with higher strength and moderate plasticity, simultaneous improvement in strength (19%) and ductility (33%) was attained in the nacre-like composites, leading to superior strength-ductility synergy. The strengthening and toughening mechanism were discussed based on microstructures and fractographs. Our study offers a facile approach to fabricating large-sized nacre-like artificial composites with outstanding properties.