Investigating the Effects of Expansion Equal Channel Angular Extrusion (Exp-ECAE) on Dynamic Behavior of AA7075 Aluminum Alloy

Abstract

Expansion equal channel angular extrusion (Exp-ECAE) is a severe plastic deformation (SPD) operation for processing bulk materials. <span lang="EN-GB">In the current study, AA7075 Al was SPD-processed by expansion equal channel angular extrusion (Ex-ECAE) at various temperatures and ram velocities. Then, using split Hopkinson pressure bar (SHPB), the severely deformed products were compressed at room temperature and strain rates of 0.1~3000 s^-1. Both the strain rate sensitivity (SRS) and the apparent activation volume (AAV) were determined for all deformed samples. The results revealed that the Ex-ECAE operation has noticeably increased the SRS. The tensile strength at a strain rate of 3000 s^-1 was 6 times increased by conducting Ex-ECAE at 100 °C and with a ram velocity of 7 mm/min. Ex-ECAE was also capable of considerably decreasing the AAV. The results showed </span>the yield stress of both the Exp-ECAE and the annealed samples increased with increasing the strain rate. Also, <span lang="EN-GB">the results showed that after the Exp-ECAE process, the AAV reached to 6.3 <em>b</em>³ </span>from the initial values <span lang="EN-GB">of 118.5 <em>b</em>³ in the annealed state.</span>