强磁场对Cu-40%Pb偏晶合金凝固组织的影响

Solidification Structure of Cu-40%Pb Monotectic Alloy in High Magnetic Field

在强磁场作用下进行了Cu-40%Pb偏晶合金的凝固实验,研究了偏晶共生组织的凝固形态.实验结果表明:12 T强磁场的作用使富Pb组织形态发生变化,试样中部及下部的棒状相伸长,在试样中部形成了超长规则排列的棒状富Pb相.凝固前沿富Pb小液滴的运动及分布是决定共生组织中棒状相形态的决定性因素.施加强磁场可改变富Pb基体的表观黏度,从而对凝固前沿的富Pb小液滴运动及附近流体流动产生抑制作用,这被认为是规则排列的超长棒状相的形成原因.

The solidification structure of Cu-40% Pb monotectic alloy was experimentally investigated in a 12 T high magnetic field, mcludmg the coexistent monotectic morphology of solidification. The results showed that during the solidification in such a magnetic field the rodlike and regularly arranged extra-long Pb-rich phase forms at the centre of specimen. The high magnetic field enables the Pb-rich phase in solidification structure to have a elongating effect, so the percentage elongation is efficient to analyze the result from the elongation effect. The high magnetic field can also hold back the motion of Pb-rich phase droplets and the melt flow along the solidification front, which is just the reason why the extra-long and regularly arranged monotectic structure forms.