Laser nitriding of an intermetallic TiAl alloy with a diode laser

Laser nitriding of a Ti-Al-Nb-B intermetallic alloy with a diode laser was investigated. Different processing parameters were used to obtain a crack free, smooth and wear resistant TiN layer. A superficial roughness (Ra) of less than 0.4 μm without postnitriding finishing operations was achieved using a laser energy density of 0.25 kJ/cm2. Hardness measurements and microstructural analysis were done on the laser nitrided samples. Reciprocating wear tests comparing a PVD nitrided sample, an untreated sample and different laser nitrided samples indicated that the laser nitrided sample with the lowest surface roughness exhibited the least amount of wear and had the lowest friction coefficient.