MECHANICAL PROPERTIES OF AL-ZN-MG-CU ALLOYS PROCESSED WITH HIGH-PRESSURE TORSION

摘要

It has been reported that tensile strength of the 7075 alloy, a commercial age-hardenable Al-Zn-Mg-Cu based alloy, is significantly improved by high-pressure torsion (HPT). The present research has been performed to study the effects of alloy compositions and process conditions on mechanical properties in Al-Zn-Mg-Cu alloys processed with HPT. Several Al-Zn-Mg(-Cu) alloys were melted and cast, and disc specimens of 10 mm diameter and 1 mm thick were machined from the homogenized ingots. The disc specimens were solution treated and subjected to HPT with a compression stress of 2 GPa at a rotation speed of 1 rpm. The torque at the steady state increased with increasing amount of alloying elements. The strength after HPT also increased with increasing amount of alloying elements. The tensile strength of Al-10%Zn-2%Mg-2%Cu alloy, in mass %, was increased to about 900 MPa by 10 turns of HPT processing.