الفهرس 
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Abstract
Al-5%Ti-1%B and Al-5%Ti-1C master alloys were used to grain refine some aluminium alloys. The factors that affect the efficiency of grain refiners (addition rate, holding time, pouring temperature and metal composition) were studied. Thermal analysis was used to evaluate the effeciency of the two grain refiners o\in parallel with a conventional method (KBI test). The characteristic parallel with a conventional method (KBI test). The characteristic parameters of the cooling curves have been correlated to the addition rate of the grain refiners. The effect of the grain refinemet on the mechanical properties (ultimate tensile strength and elogation) and physical properties (electrical resistivity) of commercial pure aluminium (99.7%Al) refined by Al-5%Ti-1%B and Al-5%Ti-1%C master alloys was also studied.
It was found that Al-5%Ti-1%C master alloy is more efficient grain refiner than Al-5%Ti-1%B. Also, it was found that thermal analysis could be used as a tool to evaluate the efficiency of the grain refiners of aluminium alloys prior to casting.