An Experimental Investigation on Microstructural, Mechanical and Biocompatibility Properties of Ti6Al4V Alloy Subjected to Equal Channel Angular Pressing Process

The work is focused to study the strength of titanium grade5 alloy (Ti6Al4V) by equal channel angular pressing (ECAP) process through the grain refinement. The low density, corrosion resistance and biocompatibility properties of titanium alloy hold wide application in biomedical implants and other engineering applications. This paper demonstrates about ECAP of titanium grade 5 alloy up to four passes at room temperature. The microstructure, mechanical and bio-properties were analyzed. The yield strength was developed from 620 to 905 MPa and the ultimate tensile strength from 950 to 1200 MPa due to the grain refinement caused by the action of slip and twinning. The micro-hardness value was enhanced from 280 to 350 Hv because of accumulation of twinning and migration of grain boundaries. The enhanced strength due to the strain hardening through ECAP and the rapid formation of titanium oxide layer on the surface improved the corrosion resistance of Ti6Al4V alloy from 2.0 mm/year (as received) to 0.5 mm/year (ECAPed). The effect of ECAP on cyto-compatibility proved that the cell viability and original cell attachment were significantly developed due to the large amount of grain boundaries. It was verified that equal channel angular pressing process is an efficient method for the grain refinement in Ti6Al4V alloy and consequently enhancing its microstructural, mechanical and bio-properties.