Enhancement of strength and ductility by interfacial nano-decoration in carbon nanotube/aluminum matrix composites

Abstract

Aluminum (Al) matrix composites gain tremendous attention as candidates for lightweight structural materials. Interfaces between the matrix and reinforcements, long-standing concerns, are critical in determining the mechanical properties of Al matrix composites. Unlike the conventional thoughts that focus on raising the interfacial wettability, a novel interfacial nano-decoration strategy is reported to enhance the interfacial adhesion by forming a diffusion interface between Al and carbon nanotubes (CNTs) through copper (Cu) coating on the surface of CNTs. The resulted Cu-rich nanolayers through this strategy compromise the large interfacial misfit strain between Al and CNTs. Such unique interfacial structure improves the strengthening efficiency of CNTs and benefits the plastic deformation of the Al matrix, and thus contributes to a simultaneous increase in strength and ductility and breaks the ubiquitous strength-ductility trade-off dilemma in the structural material design. Consequently, we achieve an exceptional combination of tensile strength (391 MPa) and tensile elongation (15.7%) for our composite that surpasses its counterparts. The present tactic thus paves a new way to process high-performance Al matrix composites.