机械振动对AZ91充型凝固中铸件-铸型传热的影响

发布时间：2019-06-20 12:18

【摘要】：研究了AZ91镁合金在充型凝固过程中不同振动频率对镁合金充型过程、凝固方式和铸件-铸型间隙的影响机制,并自主设计铸件-铸型界面传热效率装置,探讨了机械振动对铸件-铸型界面传热的影响。结果表明,机械振动使充型过程中合金液流体雷诺数变大,层流边界层厚度减小;破坏凝固初期型腔壁已凝固薄层,改变镁合金的凝固方式,使合金晶粒细化、改变晶体内部相形态及分布;凝固后,使铸件-铸型间隙处于动态变化过程。进而影响了铸件-铸型界面间的传热。当振动频率分别为0,20,50 Hz时,模具所达到的最高温度值分别为365.3,372.1,377.1℃,模具温度上升至最大温度值所需的时间依次为111,100,91 s,振动频率从0Hz增大到50 Hz,模具所达到的最大温度值逐渐增加,模具温度上升至最大温度值所需的时间逐渐减少。
[Abstract]:The influence of different vibration frequency of AZ91 magnesium alloy on the filling process, solidification and casting-casting gap of the magnesium alloy during the filling and solidification process is studied, and the influence of mechanical vibration on the heat transfer of the casting-casting interface is discussed. The results show that the Reynolds number of the alloy liquid in the filling process is increased, the thickness of the laminar boundary layer is reduced, the solidified thin layer of the initial cavity wall of the solidification is destroyed, the solidification mode of the magnesium alloy is changed, the grain of the alloy is refined, the morphology and distribution of the internal phase of the crystal are changed, and after the solidification, So that the casting-casting gap is in a dynamic change process. So that the heat transfer between the casting and the mold interface is influenced. When the vibration frequency is 0,20 and 50 Hz, the maximum temperature value reached by the die is 365.3, 372.1, 377.1degree. C., the time required for the mold temperature to rise to the maximum temperature value is 111,100,91 s, the vibration frequency is increased from 0 Hz to 50 Hz, and the maximum temperature value reached by the die is gradually increased, The time required for the mold temperature to rise to the maximum temperature value is gradually reduced.
【作者单位】：重庆大学;国家镁合金材料工程技术研究中心;
【基金】：重庆市科技攻关计划(CSTC,2008AA4029)
【分类号】：TG292

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