深过冷Cu-37.4%Pb偏晶合金凝固行为和微观组织

Solidification Behavior and Microstructure of Highly Undercooled Cu-37.4%Pb Monotectic Alloy

用熔融玻璃净化与循环过热相结合的方法 ,研究Cu 3 7.4%Pb偏晶合金过冷熔体凝固组织的演化规律和熔体过冷度及形核率对相分离的影响。研究表明 :对于偏晶合金 ,当过冷度 <15 0K时 ,由于初生相L2 的长大被抑制 ,形成Pb分布在α枝晶间的均匀凝固组织 ;当过冷度 >15 0K时 ,随着过冷度的增大 ,由于Ostward熟化和凝并的加强 ,L2 液滴尺寸增加 ,导致L2的液相分离 ,凝固组织中的Pb颗粒尺寸经历由小变大的过程 。

The microstructure evolution patterns and the phases separation of Cu-37. 4%Pb monotectic (mass percentage) alloy caused by undercooling and nucleation have been investigated with glass fluxing technique combined with cycling processes of superheating and cooling. It indicates due to the growth of primary phase L2 restrained, the microstructure with Pb distributed in interdendritic spacing is formed within undercooling less than 150 K.