Identifying heterostructured materials

Heterostructured materials comprise domains with markedly different properties whose interactive coupling produces synergistic effects beyond the rule of mixtures. As the field advances, a key question is how to distinguish heterostructured materials from conventional materials that also contain microstructural heterogeneities. Here, we identify defining characteristics based on the mechanisms underlying their superior mechanical performance. Forward stress plays a decisive role in governing the mechanical behavior of heterostructured materials but is negligible in conventional materials. Microstructurally, heterostructured materials contain plastically deformable hard domains. We also briefly discuss design strategies for representative heterostructures.