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研究了一种添加Ce并具有高Cu/Li的新型Al-Cu-Li-Ce合金在双极均匀化热处理过程中微观结构的演化过程,并重点探讨了该合金中t1(Al8Cu4Ce)相的形成过程及其形成机制。在凝固过程中Ag,Mg富集的粗大的T_B(Al_7Cu_4Li)相和原生的Al Cu Ce相共同形成。双极均匀化热处理后有2种类型的t1相出现。该相的形成模式包括,通过Ce不断的由Al基体向在T B相上新形核的t1相扩散并导致该粒子不断长大,以及原生的Al Cu Ce相通过不断缩水并伴随Cu,Ce向各个方向扩散,由之转变为细小弥散的t_1相。同时分析发现在合金凝固过程中产生的这种先析Al Cu Ce相,不但能够促进晶粒形核,同时能够阻止晶粒进一步长大,最终导致含铈的铸态合金晶粒得到细化。
The evolution of the microstructure of a novel Al-Cu-Li-Ce alloy with Ce added with high Cu / Li during the bipolar homogenization heat treatment was investigated. The formation of t1 (Al8Cu4Ce) phase in the alloy was also discussed Process and its formation mechanism. In the solidification process Ag, Mg-rich coarse T_B (Al_7Cu_4Li) phase and the native Al Cu Ce phase co-formed. There are two types of t1 phase after the bipolar homogenization heat treatment. The formation of this phase includes the continuous diffusion of Ce from the Al matrix to the newly nucleated Ti phase on the TB phase and the continuous growth of the particles, as well as the continuous reduction of the native Al Cu Ce phase with the concomitant reduction of Cu, Ce Diffusion in all directions, from which into small and dispersed t_1 phase. At the same time, it was found that the Al-Cu Ce phase produced during the solidification of the alloy can not only promote grain nucleation, but also prevent further growth of the grains, finally resulting in refinement of the as-cast alloy grains containing cerium.