基于小润湿角下脉冲磁场的凝固形核模型

发布时间：2018-02-27 10:20

  本文关键词： 晶粒细化 异质形核 脉冲磁场 小润湿角 临界形核半径 临界形核过冷度　出处：《东北大学学报(自然科学版)》2015年04期 　论文类型：期刊论文

【摘要】：基于Ma形核模型,理论分析了异质形核基底小润湿角下脉冲磁场金属凝固的异质形核过程,建立了凝固形核模型.考察脉冲磁场磁感应强度对金属凝固临界形核半径及临界形核过冷度的影响.结果表明:该模型中体系Gibbs自由能与异质形核基底形状系数无关.在低过冷度金属凝固条件下,当脉冲磁场磁压力功与金属熔体固液自由能差在同一数量级时,脉冲磁场可有效减小凝固形核的临界半径;在大过冷度(大于20℃)金属凝固条件下,脉冲磁场对金属凝固临界形核半径的影响可忽略.金属凝固异质形核基底粒径较大时,临界形核过冷度随脉冲磁场磁感应强度增大而有效减小.
[Abstract]:Based on the Ma nucleation model, the heterogeneous nucleation process of metal solidification in pulsed magnetic field at small wetting angle of heterogeneous nucleation substrate is theoretically analyzed. A solidification nucleation model was established. The influence of magnetic induction intensity of pulsed magnetic field on the critical nucleation radius and the critical nucleation undercooling of metal solidification was investigated. The results show that the Gibbs free energy of the system and the shape coefficient of the heterogeneous nucleation substrate in the model are obtained. No. Under the condition of solidification of metal with low undercooling, When the magnetic pressure work of the pulsed magnetic field is of the same order of magnitude as the solid-liquid free energy of the metal melt, the critical radius of the solidification nucleation can be effectively reduced by the pulsed magnetic field, and under the condition of large undercooling (> 20 鈩，

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