Spark Plasma Sintering of Ultra-High Temperature Ceramic Carbides: FromConventional Methods Toward Nano-Engineered Composites

TaC and HfC are thought to have the highest melting among all materials at near ۴۰۰۰ °C. Thebinary solid solution of TaC and HfC (Ta۴HfC۵) is also considered as the most refractory materialwith the melting point over ۴۰۰۰ °C and valuable physical and mechanical properties. The maingoal of this work was to fabricate of Ta۴HfC۵ based composites which consolidated by means ofSpark Plasma Sintering (SPS) with addition of MoSi۲ as sintering aid and carbon nanotubes (CNTs)as reinforcement at ۲۰۰۰ °C. The effects of additives were investigated in terms of densification,mechanical properties and microstructural (SEM) evolution. It was demonstrated that the relativedensity could reach from ۹۴ % TD (for binder less sample) to near ۹۹ % for samples containingadditives, respectively, and the average Vickers hardness values were in the range of ۱۶-۱۹ MPa.The samples containing CNTs showed improved fracture toughness and, the survivability of CNTs,after spark plasma sintering, was proved by SEM investigation of fractured surfaces

کلیدواژه ها:

Tantalum Carbide ، Hafnium Carbide ، Carbon Nanotubes ، Spark Plasma Sintering.