Removing of the Niobium Rich Inclusions from Microstructure of a New Titanium Aluminide Intermetallic Alloy

Titanium Aluminide intermetallic compounds have excellent capability for utilization in engineering structures at high temperatures. In the present work، the formation of niobium rich inclusions in microstructure and aluminum evaporation during melting of a -TiAl based alloy (Ti-48Al-2Cr-2Nb-1B (%at)) has been investigated. The results show that the inclusions can not be removed even with four-stage melting، when elemental niobium is used as raw material. However by replacing Nb with NbAl3 and three-stage melting، the inclusions can be removed from microstructure completely and also aluminum evaporation will be reduced noticeably.