中文摘要：

通过将稳恒电场作用于固相线以上糊状区和液相区内的Al-9Si合金,研究电场对铝合金凝固组织中初生α-Al形态、尺寸的影响规律。利用XJY-160巡检仪对合金降温凝固过程进行温度测量,同时借助光学显微镜（OM）和图像分析软件Image pro plus对Al-9Si合金进行组织分析。结果表明,随着所加载的电流密度的增大,初生α-Al晶粒尺寸先快速降低而后缓慢降低,电流密度最大值为330mA·mm^-2。稳恒电场的Pinch效应和热电磁流体（TEMHD）效应阻止了初生α-Al树枝晶向发达趋势生长。

英文摘要：

Through exerting a steady electric field on A1-9Si binary alloy in the mushy zone and liquid phase zone above liquidus,influence of electric field on the morphology and size of the primary a-A1 in solidification microstructures of aluminum alloy was investigated. Temperature data during the cooling process of A1-gsi melt was measured and collected with temperature recording instrument XJY-160, and the solidification microstructure was analyzed by OM （optical microscope） and Image pro plus software. The results show that with the increase of current density, the size of primary a grains are decreased first rapidly and then slowly under a steady electric field, and critical current density is 330 mA · mm-2. Both the Pinch effect and thermoelectric magnetohydrodynamic （TEMHD） caused by steady electric field are responsible for restraining dendirtic growth of the primary a-A1 grains in the A1-9Si alloy.