Co-Cu-Pb三元合金的快速凝固组织及电学性能研究

Study on Rapid Solidification Microstructure and Electrical Property of Co-Cu-Pb Ternary Alloy

采用单辊快速凝固技术研究Co-Cu-Pb三元难混溶合金薄带的快速凝固组织特征及电学性能,并通过将金属熔体热传导方程与Navier-Stokes方程相耦合,理论计算合金薄带的冷却速率。结果表明:在急冷快速凝固条件下,Co-Cu-Pb三元难混溶合金薄带的凝固组织由优先生长的Co(Cu)相枝晶骨架和枝晶间的富Pb相组成。随着冷却速率的增大,Co(Cu)相枝晶尺寸明显减小,凝固组织均匀性得到改善;而随着Pb含量的增大,少量的Pb相析出存在于Co(Cu)相枝晶干上。冷却速率的增大,合金薄带组织均匀性引起电子散射源减少,导致自由电子的散射作用减弱,使得合金薄带的电阻率减少。而合金中Pb含量的增大,减少了导电的有效电荷数,使得合金薄带的电阻率增大。快速凝固技术有效地改善了Co-Cu-Pb难混溶合金薄带的凝固组织均匀性和电学性能。

The rapid solidification microstructure characteristic and electrical property of Co-Cu-Pb ternary immiscible alloy ribbon are investigated by using the rapid solidification with a single roller experimental apparatus. Through coupled the melt heat conduct equation and Navier-Stokes equation, the cooling rates are calculated theoretically. The results show that：Under rapid solidification conditions, the microstructure of alloys ribbons are consists of Co（Cu） phase dendrite and Pb-rich phase mainly distributed in dendrite boundary. With the rise of cooling rate, the size of Co（Cu） phase dendrite is decreased and its microstructure is remarkably refined. A small quantity of fine Pb phase precipitates inside dendrite branch with the rise of Pb content. The uniformity of the solidified microstructure is improved. With the increase of cooling rate, the electron scattering sources are decreased and the free electron scattering effect is weakened, which resulting in the decreasing of alloy electrical resistivity. And with Pb content increasing, the number of conductive effective charge is reduced, resulting in the increasing of alloy electrical resistivity. Rapid solidification could effectively improve the solidified microstructure uniformity and electrical properties of Co-Cu-Pb alloy ribbon.