Taper formation mechanism and Surface integrity assessment in AWJM of Ti-6Al-4V alloy

Abstract

Titanium alloy Ti-6Al-4V alloy find its suitability for aerospace applications along with compatibility with biological component. Creation of hole is common requirement in application of alloy; these holes are created using abrasive water jet machining with variation of parameters against L25 orthogonal array of Taguchi design. The work is aimed at obtaining a high-quality surface finish, kerf taper angle as low as possible and maximized machining rate (mm/sec), relying on abrasive water jet machining (AWJM). The process parameters [Water pressure, Stand-off distance, Abrasive flow rate and transverse speed (in terms of Quality)] were also systematically evaluated to explore combined effect upon machining rate and surface integrity by plotting contour plot of responses. complex proportion assessment (COPRAS) multi-criteria decision-making technique that delivers balancing machining setup for number of process parameters which can provide maximum geometrical accuracy while maintaining satisfactory surface finish and production rate at 45 kPsi, abrasive flow rate at 300g/min, and transverse speed in 75 mm/min at quality 5 keeping standoff distance as 2 mm. unique finding obtained by Kerf taper measurement technique which indicate that the response is proportionally connected with depth of penetration, also not uniform throughout the depth. Experimental results exhibit least deviation of machining rate, moderate deviation of surface roughness while maximum variation is observed in the kerf taper angle and appeared highly sensitive. SEM and digital microscopic morphology confirm the mechanism of surface integrity deviation and taper formation and validate the statistical findings.