Microstructure and Tribological Properties of Laser Surface Alloyed TiN and TiC Reinforced Composite Coatings on TiAl Intermetallic Alloy

Laser surface alloying with gaseous nitrogen and carbon, TiN and TiC powder pre-coatings, respectively were utilized to improve the wear resistance of the TiAl intermetallic alloy Ti-48Al-2Cr-2Nb by producing rapidly solidified TiN and TiC reinforced wear resistant metal matrix composite coatings. The microstructure of the laser surface alloyed composite coatings on Ti-48Al-2Cr-2Nb substrate was characterized as functions of laser surface alloying processing conditions. The wear resistance was evaluated under dry sliding and fretting wear conditions. Results show that the hardness and wear resistance of Ti-48Al-2Cr-2Nb were significantly enhanced after laser surface alloying both with gaseous nitrogen and with carbon, TiN and TiC powder pre-coatings. The hardness and wear resistance of the TiAl intermetallic alloy were significantly enhanced after laser surface alloying treatment.