摘要
研究了Al 18%Si合金在10 T梯度强磁场下加热至半固态和全熔态后的凝固过程, 观察了初生硅的分布和形态, 测定了其冷却曲线。结果表明: 在磁场的磁感应强度和磁场梯度的乘积Bz·dBz/dz为正时, 初生硅向上部聚集; 而在Bz·dBz/dz为负时, 初生硅向下部聚集; 在强磁场下, 加热至全熔态冷却下来的凝固组织中初晶硅的形态发生了明显的改变, 由板片状转变为块状, 初晶硅显著细化。对强磁场细化初晶硅的机制进行了探讨。
The solidification of Al-18%Si alloys heated to the mushy zone or completely melt in a gradient high magnetic field was investigated experimentally. The cooling curves during the solidification were measured, and the morphology of the primary Si was examined. It is shown that the primary silicon grains tend to segregate on the upper portion of the samples with the positive B_z·dB_z/dz ; while the primary silicon grains tend to gather on the bottom of the samples with the negative B_z·dB_z/dz. With the gradient high magnetic field, the silicon grains gathered on the upper portion of the sample are small equiaxed grains, and those on the bottom of the sample are coarse flake, the same for the grains in the case of no magnetic field. These phenomena were discussed according to the magnetization of silicon in a high gradient magnetic field.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2005年第1期72-78,共7页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(50234020
50225416
59871026)
科技部基础研究快速反应项目
上海市科委重点基础研究项目
上海市国际合作项目(04DZ14002)
关键词
梯度磁场
Al-18%Si合金
磁场力
凝固
gradient magnetic field
Al-18%Si alloy
magnetic force
solidification
