PLASTIC DEFORMATION MAGNESIUM ALLOY HAVING EXCELLENT THERMAL CONDUCTIVITY AND FLAME RETARDANCY, AND

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The present invention relates to a magnesium alloy having excellent thermal conductivity and flame retardancy and facilitating plastic deformation, the magnesium alloy containing 0.5-5 wt% of zinc (Zn) and 0.3-2.0 wt% of at least one of yttrium (Y) and mischmetal in magnesium, wherein the total amount of alloying elements is 2.5-6 wt% by selectively adding 1.0 wt% or less of one or more of calcium (Ca), silicon (Si), manganese (Mn) and tin (Sn), in accordance with circumstances. The method for preparing the alloy is characterized by preparing a molten alloy of magnesium and zinc in a melting furnace, adding high-melting-point alloying elements in the form of a master alloy thereto, melting the same, and then preparing a magnesium alloy cast material with small segregation by carrying out mechanical stirring while a cast material is cooled in a continuous casting template to which a molten magnesium alloy is supplied, and then molding is carried out through a tempering process such as rolling, extrusion or forging after removing the chill zone of the cast material or carrying out diffusion annealing. According to the present invention, there are effects of : improving ductility by the action of alloying elements inhibiting the formation of lamellar precipitates caused by a low melting point eutectic phase in a magnesium base texture; enabling extrusion even with a pressure of 1, 000 kgf/cm2 or less since the plastic deformability of a magnesium alloy is improved; allowing wide application thereof as a radiation plate or a structural material of portable electric home appliances, automobile and aircraft parts, and the like since the present invention is suitable for a use requiring fire safety by having a thermal conductivity of 100 W/m·K or more and a flame retardancy satisfying the requirements of aircraft material usage; and contributing to weight reduction.