不同温度场下AZ31镁合金筒形件反挤压成形规律研究

To invesgated the effect laws of different temperatures on the backward extrusion forming of AZ31 magnesium alloy tubular parts, numerical simulation and experimental investigation were used. By changing the temperature of billets under the die temperature of 200 ℃, the distribution law of temperature field and strain field, as well as the microstructure and mechanical properties of the tubular parts were investigated. The results show that during the deformation process, a certain temperature field is formed by the billet body heat, heat transfer between die and billet and the heat of deformation. The maximum temperature reaches 290 ℃ even when the billet is at room temperature. Under different conditions of billet temperature, the effective strain mainly concentrates on the corner and inner wall of tubular parts, and the effective strain decreases gradually along the inner wall to the outer wall at the same height. In addition, the microstructure and the mechanical properties of the tubular parts formed by backward extrusion are improved obviously. Compared with the original materials, the average grain size of the tubular parts formed by the billet at room temperature decreases from 25.58 to 2.39 μm, the yield strength and tensile strength increase by 119% and 74.7% respectively, and the elongation increases by 67.7%. The analysis shows that dynamic recrystallization occurs during the backward extrusion process, which significantly refines the grain and improves the mechanical properties of the material.