Newly developed heat resistant magnesium alloy by thixomolding

Thixomolding of magnesium alloy is an environmentally friendly and safe casting process. This process is capable of near net shape casting from solid feedstock in a single step by injecting metallic slurry into a die cavity with high pressure at semi-solid or fully melted state. In the present work, we investigated the effects of the chemical composition on the creep resistance at elevated temperatures, the corrosion resistance at room temperature and the fluidity during thixomolding about the Mg-Al-Ca-Mm-Sr alloys. Obtained results are the following. (1) The creep resistance increased with increasing additional Ca or Sr content to AM60B. The effect of Ca was larger than that of Sr. The corrosion resistance decreased with increasing Ca content. (2) No significant differences of the corrosion and creep resistance were observed within the Al content of 4 to 8mass% in Mg-Al-3mass%Ca alloys. (3) More than 0.5mass% Mm addition to ACa63 was effective in the corrosion resistant to a certain extent without outstanding decrease of the creep resistance. Moreover, a practical corrosion rate was achieved by more than 0.01mass% Sr addition to ACaE6305. (4) A slight addition (0.01 mass%) of Sr to ACaE6305 was effective in improving the fluidity at a thin wall (1 mm) cavity with thixomolding.