Microstructure evolution and grain refining performance of new green kind of Al–5Ti–C master alloy

Abstract

Al–5Ti–C alloy was prepared and the microstructure evolution during the remelting process and its grain refinement performance toward pure aluminium were investigated. The results show that Al–5Ti–C alloy with a more uniform microstructure was successfully prepared, and it was composed of Al, TiAl3 and TiC. At a remelting temperature of 730°C, with the increase in heat preservation time of remelted melt, the originally dispersed TiC was aggregated and pushed toward grain boundaries by α-Al, while TiAl3 dissoluted, aggregated and grew. At a temperature of 1000°C, with the increase in heat preservation time, not only TiC aggregated, but also the size and morphology of TiAl3 were changed significantly as well, the TiAl3 turning in morphology from lump-like or strip-like into coarse needle-like and flake-like grains. The grain refinement experiments show that Al–5Ti–C and remelted Al–5Ti–C master alloy have good grain refining performances.