A novel high-strength Al-based nanocomposite reinforced with Ti-based metallic glass nanoparticles produced by powder metallurgy

摘要

A novel Al-based composite reinforced with Ti-based metallic glass (MG) nanoparticles was fabricated by powder metallurgy through mechanical alloying combined with hot extrusion. During the ball-milling process, MG microparticles were refined into nanosized particles through severe plastic deformation. Hot extrusion of the milled powders resulted in a dense and uniform dispersion of the metallic glass nanoparticles in the Al-7075 matrix. This unique homogeneous structure led to a significant enhancement of strength without adversely affecting the plasticity, thus developing super-high specific yield strength. The yield strength increased from 297 MPa for Al-7075 matrix to 530, 610, 880, and 1014 MPa for the composites milled for 10, 15, 30, and 50 h, respectively. A critical analysis of the different factors contributing to the strength of the composites was carried out. Grain refinement, Orowan strengthening, and dislocation–dislocation interactions were demonstrated to be the most important contributors to the enhanced strength of the nanocomposite.