挤压态ME20镁合金退火工艺优化

Annealing Process Optimization of ME20 Mg Alloys As-extruded

研究了挤压态ME20镁合金经不同温度、时间退火后的组织性能,得出了优化的退火工艺。结果表明,经623K×4h(空冷)退火后的板材具有最优的力学性能,抗拉强度199.9MPa,伸长率19.8%,抗拉强度与挤压态相比变化不大,而伸长率提高了近40%。随退火温度的升高,得到最高伸长率的退火保温时间有明显的缩短趋势。退火态试样拉伸断裂时出现了较明显的缩颈。SEM观察表明,断口呈撕裂棱与韧窝共存的形貌,韧性断裂特征明显。

The microstructures and properties of ME20 magnesium alloy as-extruded after different annealing processes were investigated. The results show that the better properties with the tensile strength of 199.9 MPa and the elongation of 19,8%, respectively, can be obtained after annealing at 623K for 4 h and air-cooling, in the mean time, the elongation value increases by 40% than that of as-extruded sheets while the strength remains almost same. The annealing hold time corresponding with the higher elongation shorten with the increasing of annealing temperature. There is legible necking on broken tensile specimen. The behavior of fracture shows obvious characteristic of ductile rupture, with many tearing edges and cavities.