Microstructure Change of AZCa912 Magnesium Alloy Continuous Casting Bar by Hot Compression

AZCa912, 8.8mass%Al-0.68mass%Zn-0.25mass%Mn-1.9mass%Ca-Bal.Mg, continuous casting bars were formed and their hot compression properties were measured. AZCa912 alloy is a noncombustible magnesium alloy. AZCa912 bars 50 mm in diameter were formed by a direct chill continuous casting method. The surfaces of the bars had excellent metallic luster. Grain sizes in the bars were 148, and the dendrite arm spacing was 16.9 μm. Cracks on the side surfaces of the samples were formed by compression at 250-300°C, 0.01-1/s and 350°C, 1/s. However, inner cracks were not observed and-5 μm fine-grains were formed. Some samples had an unchanged casting structure after hot pressing, and the percent of the structure remaining unchanged decreased with low-temperature compression.