METHOD FOR PRODUCTION OF MASTER ALLOYS AND MASTER ALLOY FOR GRAIN REFINING TREATMENT OF ALUMINIUM MELTS

摘要

PCT No. PCT/SE88/00258 Sec. 371 Date Jan. 16, 1990 Sec. 102(e) Date Jan. 16, 1990 PCT Filed May 19, 1988 PCT Pub. No. WO88/09392 PCT Pub. Date Dec. 1, 1988.A method for the production of master alloys intended for grain refining of aluminum melts and being of the type which comprises of aluminum and 1-15 percent by weight titanium, where titanium is present in the form of intermetallic crystals of titanium aluminide in combination with additives of carbon and/or nitrogen. The method is characterized by adding carbon and/or nitrogen to the aluminum melt in an amount corresponding to at least 0.01 percent by weight in the resultant solidified material. The addition of the carbon and/or nitrogen is effected in elemental form or in the form of dissociable carbon and/or nitrogen containing compounds, making said addition before of during an established thermodynamic state of dissolution of existing crystals of titanium aluminide, and bringing the melt into a thermodynamic state where crystals of titanium aluminide present grow in size and thereafter causing the melt to solidify. Also a master alloy produced according to the above method is claimed.