Effect of Ti/B4C ratio on the microstructure and mechanical characteristics of TIG cladded TiC-TiB2 coating on Ti-6Al-4V alloy

TiC-TiB2 based composite coatings were fabricated on Ti-6Al-4V substrate by TIG cladding process using titanium (Ti), and boron carbide (B4C) preplaced powder mixture at different weight ratio (Ti:B4C = 5:1, 3:1 and 3:2). The effects of Ti/B4C powder ratio on the formation of the coating, their morphology and mechanical behavior namely the micro-hardness and the sliding abrasive wear characteristic were investigated for different processing conditions. The microstructural analysis revealed that for using lower B4C content (5Ti:B4C) in the precursor, at relatively lower current the formation of a uniform coating is possible, whereas for using higher B4C content (3Ti:2B(4)C) larger processing current was required to obtain a uniform coating with appropriate bonding. On the other side, the hardness and the wear resistance of the coatings are found much higher for higher B4C content in the precursor.