Hierarchically structured bi-continuous Mg–Ti interpenetrating-phase composites

|Biological materials in nature demonstrate hierarchical 3D interpenetrating-phase structures, which contribute to their exceptional mechanical and functional properties. However, replicating these architectures into metallic materials remains a significant challenge. In this study, a series of Mg–Ti interpenetrating-phase composites with one, two, and three levels of structural hierarchy were fabricated using a combined approach of melt infiltration, liquid metal dealloying, and space holder addition. These composites exhibit a multimodal distribution of characteristic structural dimensions, with bi-continuous and mutually interpenetrated Mg and Ti phases across various length scales in 3D space. The compressive properties of these composites were investigated, and their Young's modulus was theoretically modeled based on the geometric characteristics and volume fractions of constituent phases. This study presents an effective approach for developing new high-performance interpenetrating-phase metal composites with hierarchical structures in bulk form. • A combined approach was developed for constructing hierarchical structures in metals. • Hierarchical bi-continuous Mg–Ti interpenetrating-phase composites were fabricated. • The composites exhibited multimodal distribution of characteristic dimensions. • Compressive properties were investigated with Young's modulus theoretically modeled. • New avenues are opening for the development of high-performance metal composites.