Enhanced mechanical properties of nanostructured TiSi2-NbSi2 composite rapidly sintered by pulsed current activated heating

摘要

Despite of many attractive properties, the low fracture toughness of refractory metal silicides limits their wide application. One of the most obvious tactics to improve the mechanical properties has been to make fabrication of a nanostructured material and composite material. Nanopowders of Ti, Nb, and Si were fabricated by high-energy ball milling. A dense nanostructured TiSi2-NbSi2 composite was simultaneously synthesized and sintered by the pulsed current activated sintering method within three minutes using mechanically activated powders of Ti, Nb, and Si. A high-density TiSi2-NbSi2 composite was produced under simultaneous application of an 80-MPa pressure and a pulsed current. The hardness and fracture toughness of the nanostructured TiSi2-NbSi2 composite were higher than those of monolithic TiSi2 or NbSi2. This is believed to suggest that TiSi2 and NbSi2 in the composite may deter the propagation of cracks and TiSi2 and NbSi2 have a nanocrystalline.