Microstructure and properties of TiN layer on Ti6Al4V prepared by nitrogen pulsed-arc

By using nitrogen as the protective gas and reactant gas, pulsed nitrogen arc cladding technology was used to realize the synthesis of TiN layer on Ti6Al4V to improve surface characteristics. The microstructure and phase composition of TiN layer were investigated by metallurgical microscopy and X-ray diffraction (XRD)．The influence of the technological parameter on the properties of the TiN layer with pulsed arc mode were studied. The results show that compared with DC arc, the pulsed nitrogen arc technology improves the thickness and width of TiN layer. Due to the high concentration of the nitrogen ion, the thickness and microhardness of TiN layer by pulsed arc are much more than that by DC arc at the same welding heat input. TiN layer has the obvious (200) orientation. The diffraction peak of TiN is increased at pulsed arc mode. The microhardness of TiN layer is 2 600 HV at AC 200 A. The microhardness is about 7.4 times of the Ti6Al4V alloy.