Thermo-mechanical treatment of AI-5Ti-lB and AI-5Ti master alloy on its grain refining performance on aluminium

Abstract

AI-5Ti-lB and AI-5Ti master alloys in as cast. extruded and rolled conditions were studied for their grain refining performance on aluminium (Al). The AI-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.