具有网络互穿结构TiC／AZ91D镁基复合材料的一种合成方法

A new route to synthesize TiC/AZ91D magnesium matrix composites with interpenetrating networks

介绍一种新的低成本合成具有网络互穿结构TiC/ AZ91D镁基复合材料的方法——原位反应渗透法。该方法中, TiC陶瓷增强相由元素粉末Ti和C间原位反应直接合成,无需添加第三相金属粉末,仅在原位反应发生的同时熔融基体镁合金由毛细管力作用渗入(Tip+Cp)顸制块内部构成致密的具有网络互穿结构的TiC/AZ91D镁基复合材料。实验结果和理论计算表明:(1)通过精确控制(Tip+Cp)预制块的致密度,考虑原位反应发生前后形成的TiC本征体积变化,即可获得具有不同TiC陶瓷含量的网络互穿结构镁基复合材料;(2)原位合成的TiC陶瓷是一可变化学剂量比的化合物,其晶格常敷随反应条件而变化,主要取决于反应条件和原始元素粉末的足寸。

In this paper,a novel and cost-effective processing route,in situ reactive infiltration technique,was proposed to fabricate titanium carbide reinforced magnesium matrix composites (TiC/AZ91D) with interpenetrating networks. In this process, the molten Mg can penetrate the preform of (Tip+Cp) by capillary force, while the ceramic reinforcement phase TiC was synthesized in situ from elemental powders of Ti and C without any addition of the third phase metal powder. Thus,dense TiC/AZ91D composites with interpenetrating networks could be obtained. By precisely controlling the relative density of the predetermined preform,the volume fraction of the in situ synthesized reinforcement with interpenetrating network can be tailored, which was supported by experimental and theoretical comparison for the intrinsically volumetric shrinkage of the in situ formed TiC phase before and after in situ reaction. Calculation of the lattice constant of in situ formed TiC phase showed that TiC has a variable stoichiometry of C/Ti depending on the processing conditions and initial particle sizes of the elemental powders.