Influence of twist extrusion process on microstructure and mechanical properties of 6063 aluminum alloy

In this study, aluminum alloy 6063 was severely deformed by twist extrusion (TE) technique and its mechanical properties, before and after TE, was investigated using a die with the twist line slope of β = 30°. It was revealed that large strains imposed on the material by this advanced method of severe plastic deformation (SPD) led to a nano-scale ultra-fine microstructure and to an enhancement of the mechanical properties. The more passes of TE the finer grained microstructure was produced. Also with increasing the number of TE passes, yield strength, ultimate tensile strength and hardness increased, while after relative reduction of uniform elongation and elongation to failure by intermediate passes they remained almost unchanged. Therefore, both the strength and ductility of the material were improved when deformed by twist extrusion.

► Microstructure evolution of AA 6063 deformed by twist extrusion was studied.
► Grain refinement behavior of extruded samples was evaluated.
► Effect of number of TE passes on strength, ductility and hardness was also studied.
► Strains accumulated in high passes of TE led to a nano-scale ultra-fine grains.
► Twist extruded alloy showed enhancement in both strength and ductility.