反应放热法合成Al-Ti-C晶粒细化剂研究

Preparation of Al-Ti-C Master Alloy by Exothermic Dispersive Synthetic Technology

以Al,Ti,C粉末为原料 ,在Al熔体中通过粉末间的强烈放热反应合成了AlTi5C 0 .2晶粒细化剂 ,并采用OM ,XRD和SEM等分析手段 ,研究了中间合金的反应合成过程、TiC粒子的形成机制及其细化特性。结果表明 :在 670℃时 ,Ti(s)与Al(l)发生强烈的放热反应 ,在Al熔体中形成块状TiAl3粒子 ;反应释放的热量使反应区升温 ,TiAl3(s)粒子溶解于Al熔体中形成活性Ti,Ti通过扩散至C颗粒表面并与之反应形成TiC粒子 ,并呈现聚集形态 ;随保温时间的延长 ,TiAl3 粒子由块状向针片状转变 ,TiC粒子的簇状分布特征明显增强 。

AlTi 5C 0.2 master alloy was prepared by the ex ot hermic dispersive synthesis using Al, Ti and C powders in Al melt. The reactive synthetic process of the master alloy and the generation mechanism as well as r efining fe atures of TiC particulate were investigated by means of OM, XRD and SEM. The res ults showed that the explosively exothermic reaction between Ti(s) and Al(l) for med chunky TiAl 3(s) particle in Al melt at 670 ℃ with elevating the melt tem perature in the reactive zone, and in turn TiAl 3(s) particle dissolved into Al melt to generate active Ti which diffused into the surface of carbon particle t o form TiC particle in coagulative state. The TiAl 3 particle changed from chunky to flaky shapes with obviously clustered TiC distribution with prolonging holding time, resulting in slight reduction of refining performance of the mast er alloy.