Thermo-mechanical treatment of Al-5Ti-1B and Al-5Ti master alloy on its grain refining performance on aluminium

Abstract

Al-5Ti-lB and Al-5Ti master alloys in as cast. extruded and rolled conditions were studied for their grain refining performance on aluminium (Al). The Al-5Ti-1B and Al-5Ti master alloys were prepared by the reaction of K₂TiF₆,KBF₄ and K₂TiF₆ respectively with molten Al. The performance of as cast and thermo-mechanically treated master alloys have been studied in deytaik and results showed that thermo-mechanically treated master alloys showed improved grain refining results as compared to as cast master alloys. This is due to the formation of more number of TiAl, particles that were formed during rolling and extrusion. In both the processes, the mean particle size of TiAl, decreased with increase in the reduction level of rolling. Moreover. the morphology of TiAl, in as cast condition was observed as plate like and after thermo-mechanical treatment. the morphology has been changed to blocky type and the latter was considered to be effet:tive l1udeating sites during soliditication of Al.