脉冲磁场下电磁力特性研究:理论分析  

On the Characteristics of Pulsed Electromagnetic Force:Theoretical Analysis

作　　者：华骏山[1] 张永杰[1,2] 王恩刚[1] 赫冀成[1] 

机构地区：[1]东北大学材料电磁过程教育部重点实验室,辽宁沈阳110819 [2]宝钢研究院,上海201900

出　　处：《东北大学学报（自然科学版）》2011年第1期72-75,共4页Journal of Northeastern University(Natural Science)

基　　金：国家高技术研究发展计划项目(2001AA337040);国家自然科学基金资助项目(50604005;50834009)

摘　　要：利用数学解析方法对脉冲磁场细晶技术的电磁力特性进行了理论分析.分析结果显示,单个放电周期内,随着时间变化,熔体内部脉冲电磁力方向发生瞬时改变;在某个时间段范围内,熔体内部与外部存在电磁力方向不一致的现象,而且单个周期内电磁力存在衰减特性.以上这些特性,是造成脉冲磁场致熔体振荡的主要原因.另外,对于本研究采用的工频脉冲磁场,脉冲电磁力对熔体还有搅拌作用.而且,当脉冲放电频率与凝固系统的某一固有频率相符合时,将引起共振效应,增强脉冲电磁力作用效果.The characteristics of PMF（pulsed magnetic field） force for grain refinement in solidification process was analyzed through mathematical analytic method.The main peculiarities of PMF force were shown as follows： It was found that the direction of PMF forces changes instantaneously in an individual impulse discharging period,and the PMF forces inside and outside the melt are in different directions in a certain period.In addition,the PMF force is attenuating in an individual impulse discharging period.All the three characteristics are the main reasons why the melt oscillates under PMF.Besides the characteristics as above,the PMF force has a stirring effect on melt in the medium-frequency PMF as used in this investigation.Futhermore,when the pulsed discharge frequency is equal to the natural frequency of solidification system,a resonance will happen to enhance the effect of pulsed magnetic force on solidification processing.

关 键 词：脉冲磁场 电磁力 晶粒细化 共振效应 

分 类 号：TG142.77[一般工业技术—材料科学与工程] TF777[金属学及工艺—金属材料]