Mg–Bi–Al–Mn 초고속 마그네슘 압출재의 미세조직 및 기계적 특성

초록

In this study, a developed Mg–5Bi–2Al–0.4Mn (BAM520, wt%) alloy was successfully extruded at an extremely high speed of 70 m/min. Microstructural evolution during extrusion and the microstructural characteristics and tensile properties of the very-high-speed extruded BAM520 alloy were then investigated. The homogenized BAM520 billet contained only thermally stable Mg3Bi2 phase particles without any Mg17Al12 phase with a low melting temperature. Therefore, the BAM520 alloy exhibited excellent extrudability. The very-high-speed extruded BAM520 alloy had a completely recrystallized grain structure and a typical basal fiber texture. Despite the extremely high extrusion speed of 70 m/min, the extruded BAM520 alloy had a high ultimate tensile strength of 280 MPa due to combined strengthening effects of a small grain size, numerous fine Mg3Bi2 particles, and strong basal texture.

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