变形温度和冷却方式对AZ80镁合金组织与力学性能的影响

The effects of extrusion temperatures(340 and 380 ℃) and cooling modes(air cooling and water cooling) on the microstructure and mechanical properties of AZ80 magnesium alloy tube prepared by expanding-retraction extrusion process were investigated. The microstructure and mechanical properties were characterized by optical microscope (OM), Hitachi SU5000 scanning electron microscope (SEM) and Instron 3382 universal tensile experimental machine. The results show that different extrusion temperatures and cooling modes have significant effects on the microstructure and mechanical properties of extruded AZ80 magnesium alloy. The finer grain and granular β-Mg₁7Al₁₂ phase, and the weaker basal surface texture of AZ80 magnesium alloy are obtained after extrusion at extrusion temperature of 340 ℃ and with water cooling treatment. The tensile strength and elongation of the air-cooled sample at 380 ℃ are 286.5 MPa and 8.6%, respectively, and the tensile strength and elongation of the water-cooled sample at 340 ℃ are 300 MPa and 14%, respectively.Decreasing the extrusion temperature and increasing the cooling rate can significantly improve the mechanical properties of AZ80 magnesium alloy.