抄録
Titanium aluminides have some attractive properties such as low density, high strength, high melting point and good creep, corrosion and oxidation resistances at high temperature. So, it is expected as a heat-resistant material and structural material. However, its disadvantage such as low ductility and strength at room temperature make difficult to put to practical use. This work try to improve strength at room temperature by the addition of TiC and TiB as a reinforcement. TiC/TiAl-Nb and TiB/TiAl-Nb composites were fabricated by spark plasma sintering (SPS) process using mixed powders of pure Ti, pure Al and NbC or NbB_2. TiC/TiAl-Nb and TiB/TiAl-Nb composites showed a maximum tensile strength and elongation in TiC volume fraction of 5% and TiB volume fraction of 15%. The Vickers microhardness increased as volume fraction of reinforcement increased. The addition of TiC and TiB led to grain refinement. However, grain growth was observed in the composite with over the Nb atomic mass of 7%.
