脉冲电流对Sn—Pb合金凝固组织的影响

研究了脉电流流对Ｓｎ－１０％Ｐｂ合金凝固组织的实验，实验表明，粗大的富Ｓｎ树枝状初晶细化成近球状结构，提出了一个脉冲电流对凝固组织影响的唯象机制，用经典的均匀形核理论和电动力学理论导出了脉冲压力与脉冲电流之间和成核率与脉冲压力之间的关系，脉冲电流产生的大小不同的脉冲压力对晶核的形成和长大产生不同程度的影响是导致不同观测结果的基本原因。

THE INFLUENCE OF PULSE ELECTRIC DISCHARGING ON SOLIDIFIED STRUCTURE OF Sn-10% Pb ALLOY

The influence of PED (pulse electric discharging) on the solidified structure of Sn-10%Pb (mass fraction) hypoeutectic has been studied. The testing results show that the PED can modify the solidified structure from large grains with Sn-rich dendrites to finer grains with nearly globular crystals. A phenomenological mechanism has been proposed to approach how the PED affects the microstructure. The relationships between the pulse pressure and pulse current, and between the nucleation rate and pulse pressure have been derived using the classical homogeneous nucleation theory and electrodynamic theory. The different results, tested here and elsewhere, may result from the different influence of PED on nucleation and growth of grains because of the different pulse pressure with various PED.