Titanium Matrix Composites Featuring Hierarchical Heterostructures

ABSTRACT Heterogeneous structure (HS) materials, which are characterised by heterogeneous interfaces with varying mechanical and physical properties, represent a groundbreaking advancement in structural materials. Titanium matrix composites (TMCs), a typical class of heterostructured materials, are widely used in key load‐bearing aerospace components due to their superior specific strength and modulus compared to those of titanium and its alloys. However, strength enhancement in these composites often sacrifices ductility. This review explores the fabrication methods, classification, toughening, and strengthening mechanisms of heterostructured TMCs. It begins with an overview of recent research on heterostructured titanium and its alloys, followed by a discussion of composite design approaches. A detailed analysis is provided, with a particular focus on network structures as representative configurations. Taking additive manufacturing as an example, this review examines raw powder design and the additive manufacturing process. A systematic analysis of design strategies and strengthening mechanisms is presented, offering insights into the development of high‐strength, high‐toughness TMCs. The findings suggest that designing a heterogeneous reinforcement distribution to locally form a mechanical property gradient material is an effective strategy to overcome the strength‐ductility trade‐off in TMCs. Moreover, optimising configuration design is anticipated to facilitate the synergistic enhancement of both high‐temperature strength and room‐temperature ductility.