Effect of C Addition on the Microstructure and Fracture Properties of In Situ Laminated Nb/NbSi Composites.

//Nb and α-NbSi phases were detected. Meanwhile, NbC was observed, and the crystal forms of NbSi changed in the C-doped composites. Furthermore, micron-sized and nano-sized NbC particles were found in the Nb layer. The orientation relationship of NbC phase and the surrounding Nb was [001]//[010], (200) //(101) . Additionally, with the addition of C, the compressive strength of the composites, at 1400 °C, and the fracture toughness increased from 310 MPa and 11.9 MPa·m to 330 MPa and 14.2 MPa·m, respectively; the addition of C mainly resulted in solid solution strengthening.