INVESTIGATION OF THE HARDENING OF A TITANIUM-ALLOY BY LASER NITRIDING

An attempt has been made to develop a method for hardening titanium alloys by laser treatment in a nitrogen jet. The modified zone consists of a thin (5 mum) layer of titanium nitride and a layer (nearly 150 mum) of solid solution of nitrogen in titanium. Surface plastic deformation (SPD) of the treated surface decreased the roughness of the surface without any additional mechanical treatment. The optimum parameters of laser treatment and SPD were chosen to produce the nitrided surface layer with minimum roughness, no cracks and no residual stresses. The wear test indicated the real possibility of manufacturing friction joints from light titanium alloys with subsequent laser nitriding and SPD treatments.