Investigating the Effects of Expansion Equal Channel Angular Extrusion (Exp-ECAE) on Dynamic Behavior of AA۷۰۷۵ Aluminum Alloy

Expansion equal channel angular extrusion (Exp-ECAE) is a severe plastic deformation (SPD) operation for processing bulk materials. In the current study, AA۷۰۷۵ 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 ۰.۱~۳۰۰۰ s-۱. 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 ۳۰۰۰ s-۱ was ۶ times increased by conducting Ex-ECAE at ۱۰۰ °C and with a ram velocity of ۷ mm/min. Ex-ECAE was also capable of considerably decreasing the AAV. The results showed the yield stress of both the Exp-ECAE and the annealed samples increased with increasing the strain rate. Also, the results showed that after the Exp-ECAE process, the AAV reached to ۶.۳ b۳ from the initial values of ۱۱۸.۵ b۳ in the annealed state.

Keywords:

AA۷۰۷۵ Aluminum Alloy , Dynamic Behavior , Expansion Equal Channel Angular Extrusion , Hopkinson Pressure Bar , Severe Plastic Deformation