Evolution of microstructure and properties in 6063 aluminium by twist extrusion

Twist Extrusion (TE) is known as a developed and promising SPD (Severe Plastic Deformation) method which is performed by extruding a prism specimen through a die with an inner twist path. In this study, a twist extrusion die with twist line slope of 30 degrees was used and the structure and mechanical properties of Al6063 alloy were evaluated. Since the main dimensions of workpiece remained unchanged after the process, it's possible to repeat the process for several passes. The results indicated that by imposing a great strain on the sample, TE has refined microstructure and improved mechanical properties of the twisted alloy. Thus, the average grain size changed from 11μm for annealed sample to 130 nm for 16 times passed sample. 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.

Keywords:

Twist Extrusion (TE) , Al-6063 , microstructure , mechanical properties