Investigation on Microstructure and Grain Refining Performance of a New Type of Al-3Ti-1C Master Alloy

Abstract

Grain refining process plays a significant role in preventing columnar and coarse grains and it encourages fine grain formation. Although Al-Ti-B master alloys use widely as aluminium grain refiners, there are several problems in their applications. So, this kind of master alloys use less than last. Because of great properties of Al-Ti-C refiners, they can be considered as suitable candidates for use instead of Al-Ti-B master alloys. In recent years, Al-Ti-C refiners have attracted huge attention among researchers. In this paper, Al-3Ti-1C master alloy is prepared with a melting reaction method. This method involves adding graphite powder and fine titanium particles into superheated pure aluminium. Then microstructure of this master alloy is studied by scanning electron microscope (SEM) and its phases are distinguished by energy dispersive spectroscopy (EDS). In the next part, 200 ppm of Al-3Ti-1C master alloy is added to pure aluminium and its refining efficiency is compared with the condition in which TiC powders are added to aluminium melt directly. It is found that the fading time for both Al-3Ti-1C and TiC powder is about 15 minutes and in overall, grain refining efficiency of Al-3Ti-1C is more than TiC powders in 60 minutes.