GRAIN REFINER AND REFINEMENT METHOD FOR MAGNESIUM ALLOY, PREPARATION METHOD FOR MAGNESIUM ALLOY USING SAME, AND MAGNESIUM ALLOY PREPARED THEREBY

摘要

The purpose of the present invention is to provide a grain refiner and a refinement method for a magnesium alloy, a preparation method for a magnesium alloy using the same, and a magnesium alloy prepared thereby. To this end, the present invention provides a grain refinement method for a magnesium alloy and a preparation method for a magnesium alloy, the grain refinement method comprising the steps of: (step 1) coating a magnesium alloy with a protection gas, and heating and melting the same to the melting temperature of the magnesium alloy to prepare a molten magnesium alloy; adding the grain refiner for a magnesium alloy prepared by the present invention to the molten magnesium alloy prepared in step 1; and casting the molten magnesium alloy of step 2 to form a magnesium alloy cast with fine grains. According to the present invention, instead of adding a refiner having a single composition as in a conventional method, multiple types of powders showing refinement effects of different reactivities are prepared into a powder-, pellet-, rod- or wire-shape while controlling the density and mixing ratio thereof so as to be injected, thereby inducing heterogeneous nucleus generation and controlling the reactivity with a molten metal so as to maximize the refinement of a magnesium alloy, minimize the reaction concentration at an upper portion of a molten metal, and further obtain a stirring effect of the decomposition of a carbonate powder.