In-situ Formation of Ti/TiC Composite Layer on Ti-6Al-4V by Pulsed Nd-YAG Laser

This work presents in-situ formation of Ti/TiC composite layer on Ti-6Al-4V via pre-placing mixture of Graphite-Nickel and subsequently surface melting by pulsed Nd:YAG laser. The phases and microstructures of the fabricated layers were characterized by Optical Microscope (OM); Field Emission Scanning Electron M icroscope (FESEM) equipped with Energy Dispersive Spectroscopy (EDS) and X-ray Diffractometry (XRD). The effect of laser parameters on the geometry of the melted pool and in-situ formation of titanium carbide was also investigated.The experiments revealed that there are increase in the depth, width composite layer and percent of titanium carbide as the energy density increases. I t was shown that the surface layers were mainly consisted of Martensite α΄- titanium as matrix and TiC, TiC2 dendrite. The hardness of composite layer fabricated by in-situ route reached to a maximum hardness value of 1400 HV0.3, more than 4 times of that of the base Ti-6Al-4V (300-350 HV0.3).