Experimental investigation on electric discharge assisted surface modification of Ti-6Al-4 V through Titanium carbonitride powder metallurgy processed tool

Surface modification of the most widely used titanium alloy Ti-6Al-4V, which possesses less wear resistance (specific wear rate in the order of 10 ⁻⁴ mm ³ /Nm) and high wettability (contact angle 50°–60°) with the aid of Titanium carbonitride powder metallurgy processed tool used Electric Discharge Coating (PMLEDC) in deionized water is performed in this work. An average recast layer thickness of 35 ± 4 μm is attained for 30 minutes processing time at the parametric conditions of 8A current and 0.9 duty factor. Maximum material addition of 0.03 mm ³ /minute is obtained within 15 minutes processing time by the quick disintegration of the PML tool and cataphoretic deposition. A surface with a minimum roughness of 1.514 μm and a maximum contact angle of 119° is formed with the PMLEDC process. A hydrophobic surface is obtained due to the formation of a texture-like surface by the erosion of electrodes and material deposition, in addition to the presence of oxide, which causes the reduction in surface energy. Reduction in residual stress is experienced at the processed surface with a rightward shift of the peak. Almost half a reduction in wear rate was observed compared to that of the bare Ti-6Al-4V with SWR in the order of 10 ⁻⁵ mm ³ /Nm due to the effect of carbides, protective oxides, compressive residual stress and heat-affected zone.