Synergistic strengthening and toughening of alumina ceramic using two-dimensional MXene and graphene

Abstract

The inherent brittleness of alumina ceramics often leads to unexpected catastrophic failures, which significantly limits their practical applications. However, improving toughness of alumina typically result in a compromise of its strength. Achieving both high strength and exceptional damage tolerance in alumina remains a formidable challenge. To overcome this issue, we have fabricated an alumina composite that combines high strength and toughness by integrating two-dimensional MXene and graphene through solution mixing and hot pressing methods. Specifically, the optimized composite demonstrates an approximately 20 % increase in flexural strength and a remarkable 521 % improvement in fracture toughness, highlighting its exceptional durability and resistance to sudden failure. Graphene significantly enhances fracture toughness through mechanisms such as crack deflection, microcracking, crack branching, and bridging. These mechanisms effectively extend the crack propagation path and reduce the risk of sudden failure. By contrast, MXene plays a crucial role in improving flexural strength by reducing grain size. This synergistic strengthening and toughening strategy reveals new avenues for developing high-performance ceramic composites.