磁场和变质处理对初晶Si形状和分布的影响

Effects of Magnetic Field and Modification on Primary Si Morphology and Distribution

不施加静磁场条件下,Al18Si合金的凝固组织中的初晶Si相集中在试样周边,有粗长的板条状的初晶Si,中心部分是共晶组织。施加径向静磁场,在试样整个横断面上都分布有块状的初晶Si,但初晶Si大小和分布不均匀。径向施加静磁场并添加磷盐变质剂,初晶Si呈块状且更加细化,大小和分布都很均匀。

Primary silicon in the solidification structure of Al-18Si hypereutectic alloy concentrated on the edge of the sample,in which some appears to be coarse plates and strips,and the eutectic structure appeared in the center of the sample without the static magnetic field.The bulky uneven primary Si in size and distribution was distributed into the whole section of the sample with radius static magnetic field.Furthermore,imposing radius static magnetic field and adding P modifier can obtain bulky and finer primary Si with even size and distribution.