(1. 东北大学 材料与冶金学院，沈阳 110004；
2. 东北大学 轧制技术及连轧自动化国家重点实验室，沈阳 110004)
摘 要: 通过数值模拟，分析AZ31镁合金在连续流变挤压成形过程中的温度场与流场分布规律。结果表明： 辊−靴型腔内合金的温度从入口至出口逐渐降低，合金等温线向工作辊偏移；随着浇注温度的降低，辊−靴型腔内半固态区间逐渐增大；为了获得优良的半固态金属浆料，确定浇注温度为710~770 ℃；合金在辊−靴型腔内层流运动时，越靠近工作辊内表面，合金的运动速度越快；随着挤压模具扩展角的增大，挤压模具出口型材宽度上中心与两侧边部合金的温度差减小；半固态合金进入模具后呈辐射状逐层向前推进填充模具扩展腔，最后再逐渐向模具出口合拢；为了改善模腔内金属流动速度的不均匀性，扩展角以45˚为宜。
关键字: 镁合金；AZ31合金；半固态；连续挤压；流变挤压；数值模拟；温度；速度
AZ31 alloy
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110004, China）
Abstract:Through numerical simulation, the temperature and velocity distributions during the continuous rheo-extrusion process of AZ31 alloy were analyzed. The results show that the temperature of the alloy gradually decreases from the casting mouth to the exit in the roll-shoe gap, and the isothermal line deviates from the shoe side to the roll side. The semi-solid region in the roll-shoe gap increases with decreasing casting temperature. In order to prepare a good quality semi-solid slurry, the casting temperature of 710−770 ℃ is suggested. The alloy flows in the roll-shoe gap with a laminar pattern and the velocity near the roll is larger than that near the shoe. The temperature difference between the center and the side of the product at the deformation zone decreases with the increase of extending angle; the semi-solid alloy gradually fills the extending mould with a laminar pattern, then, it gathers at the exit of deformation mould. In order to modify the inhomogeneous flow of the alloy in the mould cavity, the extending angle is suggested to be 45˚.
Key words: magnesium alloy; AZ31 alloy; semi-solid; continuous extrusion; rheo-extrusion; numerical simulation; temperature; velocity
