电磁搅拌对Cu-6%Fe复合材料凝固组织的影响

Effects of Electromagnetic Stirring on Solidification Structure of Cu-6%Fe Composite

研究了电磁搅拌对Cu-6%Fe复合材料铸态凝固组织的影响.结果表明,在Cu-6%Fe合金凝固组织中存在铁相富集区域,铁相在铜基体中主要以小球状颗粒存在.电磁搅拌能细化铁相颗粒,减小铁相富集区;施加电磁搅拌后,铁相颗粒具有向铸坯中心集中和成团簇分布的趋势,大颗粒铁相主要出现在铸坯中心,铸坯外缘附近的铁相颗粒较细小.增大搅拌电流,晶粒尺寸逐渐减小,富Fe颗粒逐渐被细化,分布逐渐均匀,但富铁相颗粒向铸坯中心集中.合理的搅拌电流和频率,能使晶粒更加细化,有利于铁相的均匀分布和细化.合理的电磁搅拌电流和频率分别约为100～200A和20Hz.

Electromagnetic stirring（EMS） was applied to improve solidification structure of Cu-6%Fe composite.The results showed that spherical Fe-rich precipitates are formed in the copper matrix,and the distribution of the precipitates is inhomogeneous.The electromagnetic stirring decreases the size of Fe-rich precipitates and Fe enriched regions.After applying electromagnetic stirring,the Fe-rich precipitates are accumulated towards the centre of the casting and distribute with agminate tendency.The Fe-rich precipitates with larger size mainly locate at the centre of casting,whereas the finer precipitates are near the outer surface of casting.With electric current increasing,the grain size gradually decreases,and the precipitates are refined and distribute more uniform simultaneously.Upon a further increase,the precipitates gradually accumulate to the centre from outer surface of the casting.A rational electric current can make the Fe-rich precipitates tend to distribute uniformly.In this case,the optimal EMS current is about 100～200 A.Also an optimal EMS frequency can make the grain finer,and an appropriate frequency is about 20 Hz in this case.