Abstract |
AM30 + (0, 0.5, 1, 1.5) wt%CaO magnesium alloys were cast and oxidized at 625 ℃ and 650 ℃ in atmospheric air. The CaO particles that were added during casting allowed casting the AM30 alloys in air without using environmentally hazardous SF6 or SO2 gases. They decomposed to dissolve in the α-Mg matrix and also to precipitate along the matrix grain boundaries as Al2Ca during casting. The ignition temperatures were 584.6 ℃ for AM30, 604.5 ℃ for AM30 + 0.5 wt%CaO, and 691.7 ℃ for AM30 + 1 wt%CaO. No ignition occurred for AM30 + 1.5 wt%CaO up to 700 ℃. During oxidation, CaO-rich oxide scales formed on the alloy surface, which prevented direct contact of the alloy with air and fast oxidation of the alloy in air. |
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Key Words |
magnesium alloys, AM30, CaO, oxidation |
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