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研究了不同温度条件AZ31镁合金型材的应力应变状态变化,探讨了在单向拉伸试验条件下,其力学性能、微观组织、断口形貌的变化规律。结果表明:随着温度的升高,屈服强度从室温的203 MPa下降到230℃时的125 MPa,显著减小;170℃时,镁合金屈服强度为152 MPa,抗拉强度为242 MPa,屈强比最小,塑性成形性能最好;170℃时,型材的微观组织中仍存在大量孪晶,主要发生在晶粒内部,而在晶界附近有少量的再结晶。断裂方式从25℃时的脆性解理断裂转变为120~170℃的准解理及韧窝混合断裂,再转变为210~230℃的韧窝韧性断裂。
The changes of stress and strain state of AZ31 magnesium alloy profiles under different temperature conditions were studied. The change rules of mechanical properties, microstructure and fracture morphology under uniaxial tensile test were discussed. The results show that with the increase of temperature, the yield strength decreases from 203 MPa at room temperature to 125 MPa at 230 ℃. The yield strength of magnesium alloy at 152 ℃ is 152 MPa and the tensile strength is 242 MPa. Strong and minimal plastic forming properties of the best; 170 ℃, the profile of the microstructure there are still a large number of twins, mainly in the grain within the grain boundary in the vicinity of a small amount of recrystallization. The fracture mode changed from the brittle cleavage fracture at 25 ℃ to the quasi-cleavage at 12 ~ 170 ℃ and the dimple mixed fracture, and then changed to the ductile fracture at 210 ~ 230 ℃.