中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 36 No. 1 January 2026 |
（a Key Laboratory of Automobile Materials, Ministry of Education, School of Materials Science and Engineering, Jilin University, Changchun 130022, China;
b FAW Tooling Die Manufacturing Co., Ltd., Changchun 130000, China）
Abstract:The effects of artificial aging (T6) on the creep resistance with tensile stresses in the range of 50-80 MPa at 175 °C were investigated for an extruded Mg-1.22Al-0.31Ca-0.44Mn (wt.%) alloy. The Guinier-Preston (G.P.) zones primarily precipitate in the sample aged at 200 °C for 1 h (T6-200°C/1h), while the Al2Ca phases mainly precipitate in the sample aged at 275 °C for 8 h (T6-275°C/8h). The T6-200°C/1h sample exhibits excellent creep resistance, with a steady-state creep rate one order of magnitude lower than that of the T6-275°C/8h sample. The abnormally high stress exponent (~8.2) observed in the T6-200°C/1h sample is associated with the power-law breakdown mechanism. TEM analysis illuminates that the creep mechanism for the T6-200°C/1h sample is cross-slip between basal and prismatic dislocations, while the T6-275°C/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb. Compared with the Al2Ca phase, the dense G.P. zones effectively impede dislocation climb and glide during the creep process, demonstrating superior creep resistance of the T6-200°C/1h sample.
Key words: Mg-Al-Ca-Mn alloy; tensile creep; artificial aging; cross slip
