주조 및 불연속 석출물 미세조직을 가지는 Mg-Al 합금의 인장 특성 및 열전도도 = Tensile Properties and Thermal Conductivities of Mg-Al alloy with As-Cast and Discontinuous Precipitates Microstructures

다국어 초록 (Multilingual Abstract)

The objective of this study was to investigate the tensile properties and thermal conductivities of Mg- 9.3%Al alloy in as-cast state and heat-treated state consisting of fully discontinuous precipitates (DPs), respectively. The fully DPs microstructure was obtained by solution treatment at 405℃ for 24 h, followed by furnace cooling to RT. The as-cast alloy showed a partially divorced eutectic β(Mg₁₇Al₁₂) phase particles formed along the α-(Mg) cell boundaries. The DPs had various apparent (α+β) interlamellar spacings, which is related to different transformation temperatures during the furnace cooling. The DPs microstructure exhibited better tensile strength than the as-cast one, resulting from the higher value of elongation in response to its more homogeneous microstructure. It is noticeable that the DPs microstructure had 12.4% higher thermal conductivity in average than the as-cast one between RT and 200℃. The XRD analyses revealed that the lower Al concentration in the α-(Mg) matrix may well be responsible for the better thermal conductivity of the DPs microstructure.
(Received August 03, 2020; Revised August 10, 2020; Accepted August 31, 2020)