Effect of Precipitations on Microstructures and Mechanical Properties of Nanostructured Al-Zn-Mg-Cu Alloy

Abstract

A bulk nanostructured Al-Zn-Mg-Cu alloy with high contents of alloy elements was fabricated by cryomilling followed by spark plasma sintering (SPS) techniques. Higher strain and lower strength were obtained in the SPS-processed Al-Zn-Mg-Cu alloy samples. This is due to the agglomeration of MgZn₂ precipitated on the contact zones of powders during the SPS process. The strength of the Al-Zn-Mg-Cu alloy can be improved further by an optimize heat treatment technique, after which the precipitation-hardening effect of MgZn₂ particles precipitated homogeneously in grain interiors was enhanced. The experimental results have shown that modifying the MgZn₂ size and distribution is beneficial to improve the mechanical property of the nanostructured Al-Zn-Mg-Cu alloy.