CHARACTERIZATION OF SURFACE MMC LAYERS DEVELOPED IN TI-6AL-4V ALLOY USING COMBINATION OF SICP AND DILUTE NITROGEN ENVIRONMENT

Laser gaseous nitriding associated with powder alloying has been devel oped to modify a Ti-6Al-4V alloy. Under specific conditions, a surface MMC layer over 500 mu m was produced in the Ti-6Al-4V alloy. The proc essed specimen contains complex microstructures in the MMC surface whi ch provide a significant improvement in the surface wear resistance (2 5 times that of the base alloy). In the present work, the microstructu res developed were characterised and the phases identified to provide a better understanding and further improvements to the laser processin g. A continuous CO2 laser was used for the processing and TEM, SEM, en ergy dispersive X-ray analysis, X-ray diffraction, and electron backsc attering pattern techniques were used for the characterisation. MST/40 49.