Al-Ti-C晶粒细化剂液-固反应合成机制研究

通过SEM和TEM等分析手段，研究了液-固反应制备的Al-Ti-C晶粒细化剂合金的组织特征与细化性能，并结合热力学分析，探讨了液-固反应合成机制。结果表明：Al-Ti-C晶粒细化剂合金组织中TiAl3呈枝晶状，TiC呈颗粒状，TiC为非化学计量比化合物，可表示为TiCx形式，x=0．5～0．8，其晶格常数为0．430～0．433nm，该晶粒细化剂对纯Al具有良好的组织细化作用；液-固反应中，在液-固界面处形成瞬时高温，从而达到Ti、C反应的热力学条件，Al-Ti-C合金的形成符合溶解-析出机制，并由三组基元反应构成。

Liquid-solid Reaction Synthesis Mechanism of Al-Ti-C Grain Refiner

The microstructure characteristics and refining ability of Al-Ti-C master alloy prepared by liquid-solid reaction were investigated by SEM and TEM, and the liquid-solid synthesized mechanism was analyzed from the view of thermo-kinetics also. The results indicate that the microstructure of the Al-Ti-C master alloy is composed of dendritic TiAl_3 phase and particle TiC, where TiC belongs to non-stoichiometric ratio compound in the form of TiC_x, for x of 0.5~0.8, whose lattice contant is 0.430~0.433 nm. The master alloy can obviously refine microstructure of the Al alloy, which is resulted from the occurrence of instantaneous high temperature in the interface of liquid-solid meet the thermal-kinetics conditions of Ti and C reaction during liquid-solid reaction. The formation of Al-Ti-C master alloy belongs to the solution-precipitation mechanisms, which consists of three groups of primitive reactions.