Laser surface nitrided Ti-6Al-4V for light weight automobile disk brake rotor application

Ti-6Al-4V was laser surface nitrided using a rectangular beam intended for large area coverage at minimal processing time. The laser nitriding performed at different energy densities yielded the formation of ~120 µm thick TiN layer. Metallurgical characterization was performed using Optical Microscope (OM), Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) analysis. A hardness improvement up to 760 HV0.2 was achieved compared to the base material hardness of 315 HV0.2. The tribological characterization of laser nitrided Ti-alloy exhibited superior performance, indicating the possibility of using it as a light weight disk brake rotor than the heavier gray cast iron.