An overview of recent developments in Al metal matrix nanocomposites for strength-ductility synergy

Abstract

Researchers worldwide switched their attention from homogeneous structures to heterogeneous structures because they needed composite materials that possess both ultra-high strength and ductility. The goal is to improve the mechanical properties of composite materials by making a new “Harmonic Structure” (H.S.) with a controlled bimodal grain size distribution. A powder metallurgy-based fabrication method has been developed to achieve a controlled microstructure, including a mechanical or a bi-model milling process. Consolidated mechanical milled or bi-model milled powder has been sintered to get the final harmonic structure. The harmonic structure-designed metallic materials are solid and ductile simultaneously because of the microstructure matrix's optimized hierarchical features, which create strain delocalization during plastic deformation. So, unlike traditional homogeneous (homo)-structured materials, HS-designed materials can have synergy effects like synergy strengthening. This study shows how tailoring strain delocalization has changed the strength-ductility synergy. In addition, this study supports future innovations toward a balance between high strength and high ductility.