Microstructure of AZCa912 Continuous Casting Bar after Hot Compression

AZCa912, 8.8mass%Al-0.68mass%Zn-0.25mass%Mn-1.9mass%Ca-Bal.Mg, continuous casting bars with 50 mm in diameter were formed by a direct chill continuous casting method. AZCa912 alloy is a noncombustible magnesium alloy. The surfaces of the bars had excellent metallic luster. A dendrite structure with a DAS of around 11-23 μm and grain sizes of about 200 μm was observed. Samples with almost the same grain size and different DAS were measured at hot compression test at 250-350°C, 0.01-1/s. Crack on the side surfaces of the samples were not formed by compression at 350°C, 0.01-0.1/s. All samples had an unchanged casting structure after hot pressing, and the percent of the structure remaining unchanged decreased with low-temperature compression and wide DAS.