保温电磁搅拌对ZA-27合金凝固组织的影响

采用金相检验方法研究了保温电磁搅拌对ZA-27合金的凝固组织的影响，在电磁搅拌作用下，ZA-27合金晶粒明显细化，随着搅拌电流和强度的增加，枝晶细化更好，但当电流超过一定强度后，细化效果却不明显。在保温凝固过程中进行电磁搅拌时，晶粒细化效果更明显，其原因是在凝固过程中晶粒发生了部分重熔和大量晶粒游离。保温搅拌温度对搅拌效果影响有一临界值Tc，偏离Tc，电磁搅拌的效果将变差。

The Influence of Isothermal Electromagnetic Stirring on Solidifying Structure of ZA-27 Alloy

The influence of isothermal electromagnetic stirring on the solidifying structure by ZA-27 alloy was studied metallographically. Under electromagnetic stirring(ES), the crystal grains of ZA-27 alloy were remarkably refined. With the increment of electric current and stirring intension, arborescent crystal was gradually refined, but the effect of refinement decreased when electric current was above some critical value. As electromagnetic stirring was applied in the course of isothermal solidifying, the refinement effect of crystal grains was more remarkable. It was found that there were partial refusion and large free crystal grains during the solidifying. The temperature of isothermal solidifying contributed somewhat to the effect of ES, and there existed a critical temperature T_C at which the best effect of ES could be achieved. If the isothermal temperature deviated from the T_C, the effect of refinement would decrease with the degree of deviation.