Achieving Superior Strength‐ductility‐conductivity Combination in TiB_2p/6201 Composites via Particle Rotation and Sub‐grain Refinement

The key factor in the material design of overhead power transmission lines is to obtain a desired balance among strength, ductility and electrical conductivity. In this study, TiB2 particulate reinforced aluminum matrix composites were prepared to find a way out of the intrinsic dilemma behind this balance by tailoring the sub‐grain refinement. The interaction in the form of inhomogeneous deformation induced by the flexibility discrepancy between the rigid particles and soft matrix was studied. On the one hand, the hexagonal plate‐like TiB2 particles rotate with the inhomogeneous deformation, forcing the biggest exposed plane ((0001) basal plane) parallel to the plastic flow direction, which is beneficial for the dislocation multiplication and hindrance of dislocation slipping. On the other hand, inhomogeneous deformation generates plentiful geometry necessary dislocations, and divides the microstructure into two types: in the particle‐rich region ultrafine grains are formed, and in the particle‐free region significant sub‐grains refinement is observed. The sub‐grains with 3 wt.% TiB2 is refined from ∽897 nm to ∽248 nm. Thanks to these microstructural benefits, the composites achieve the following strength‐ductility‐conductivity combination: ultimate tensile strength is 370 MPa, elongation after fracture is 11.2%, and electrical conductivity is 51.79% IACS. Besides, the elastic modulus reaches 75.43 GPa.This article is protected by copyright. All rights reserved.