Control of microstructure and fracture toughness improvement of NbSi2/MoSi2 duplex lamellar silicides by TaC particles dispersion

 The floating-zone melting method enabled the dispersion of TaC particles in a C40-(Mo0.85Nb0.15)Si2 single crystal. By annealing the C40 crystal, coarse C11b phases were formed around the TaC particles and the precipitation of the D88-(Mo,Nb,Ta)5Si3C phase was also induced, in addition to the development of a C40/C11b lamellar microstructure. Such a microstructure containing TaC particles led to a reduction in the orientation dependence of the fracture toughness of duplex silicide crystals.