AlSi_7Mg合金半固态连铸坯料和组织形成研究

RESEARCH ON THE CONTINUOUS CAST BILLETS OF SEMI-SOLID AlSi_7Mg ALLOY AND THEIR MICROSTRUCTURE FORMATION

研究了电磁搅拌对半固态 ＡｌＳｉ７Ｍｇ合金连铸坯料组织的影响．研究结果表明：电磁搅拌功率是重要的影响因素，搅拌功率越大，球状的初生α－Ａｌ端部形态越圆整，蔷薇状的初生α－Ａｌ越少、尺寸越小，连铸坯表层的枝晶层越薄；连铸坯料中出现大量球状初生α－Ａｌ是蔷薇状初生α－Ａｌ二次臂熔断的结果，连铸坯料中出现许多蔷薇状初生α－Ａｌ结果是其二次臂未充分熔断所致。

The effect of electromagnetic stirring on the microstructure of the semi-solid AISi7Mg alloy billets produced by vertical continuous casting equipment has been investigated in this paper. The results show that the stirring power is an important factor and the larger the power, the smaller and more spherical the nondendritic primary α-Al, and the thinner the dendritic peripheral layer of the billets.The results also indicate that there are many spherical or granular primary α-Al particles in the billets,which are formed by the remelting of the secondary arm roots, and that there are also many rosette primary α-Al particles in the billets, which are retained because of lack of time for the secondary arm roots to be remelted.