【作者】 甄子胜； 毛卫民； 陈洪涛； 钟雪友；

【Author】 Zhen Zisheng, Mao Weimin, Chen Hongtao, Zhong Xueyou (School of materials science and engineering, University of Science and Technology Beijing, 100083)

【机构】 北京科技大学材料科学与工程学院；

【摘要】 本文研究了电磁搅拌条件下AZ91D合金组织的变化规律,结果表明:电磁搅拌半固态AZ91D合金组织的固相颗粒为蔷薇状或粒状α-Mg,随电磁搅拌功率的增大,蔷薇状形态逐渐消失,固相颗粒形态趋于粒状和圆整:在试验范围内,随电磁搅拌电源频率的增大,半固态AZ91D合金组织中固相颗粒形态越来越圆整。这主要是由于电磁搅拌半固态AZ91D合金组织的形成机理是以枝晶臂熔断为主,而在高频率下的电磁搅拌过程中,在搅拌室产生的集肤效应使得表面和中心出现宏观温度差,从而加强了固相颗粒随流场运动时的温度起伏,最终加速了枝晶的熔断。更多还原

【Abstract】 The effect of electro-magnetic stirring on the microstructures of semi-solid AZ91D alloy was studied in this paper. The results show that the solid particle shape in the electro-magnetic stirred semi-solid AZ91D was granular or rosette. With the stirring power increasing, the rosette shape particles disappear gradually, and the particles get more and more spherical. In the present study, higher power frequency makes the solid particle of the semi-solid AZ91D more spherical. This is because that the main evolution of the microstructure of electro-magnetic semi-solid AZ91D is proceeded by the dentritic arm melting method. Higher frequency introduces a 集肤效应 on the stirred semi-solid slurry, which makes a temperature difference between the edge part and the center part and results in a promotion of dendritic arm being melted off the dendrite grain by the large temperature fluctuation.更多还原