LASER MELTING OF TI-15AL-20NB ALLOY

Titanium aluminides have become promising materials for high-temperatu re applications, but the relatively poor oxidation resistance and elev ated-temperature strength of these alloys limit their application to t emperatures lower than 1000 degrees C. Niobium addition improves the p roperties of titanium aluminide. However, the mechanical, metallurgica l, and corrosion properties of Ti-Al-Nb may be improved by treatment w ith a laser beam. Consequently, the present study examines the propert ies of Ti-15Al-20Nb alloy subjected to the Nd:YAG laser melting proces s. Hardness in the surface region increases to twice the base material hardness, and corrosion resistance improves considerably after laser treatment.