Grain refining agent for cast aluminum or magnesium products

摘要

The invention relates to a grain refining agent for cast aluminum or magnesium products, comprising particles having an average particle size of 0.1 to 30 &mgr;m and each formed of an agglomerate of grains with each grain comprising a nanocrystal of a transition metal boride or carbide of the formula: Me_aX_b (I) wherein Me is a transition metal, X is boron or carbon, a ranges from 1 to 10 and b ranges from 1 to 20. The grain refining agent according to the invention does not require to be formed into a master alloy prior to being added to the molten aluminum or magnesium to be cast.