Microstructure and creep of Mo-ZrC in-situ composite

Microstructure and creep of are-melted and annealed Mo-40 mol%ZrC in-situ c omposite were investigated in this study. Microstructure after annealing is found to consist of primary ZrC particles and fine Mo/ZrC eutectic structu re, i.e. hyper-eutectic structure. Compressive creep tests in the temperatu re range from 1673 to 1873 K indicate that the stress exponent, n: is appro ximately 5 in the stress range from 100 to 500 MPa, and the apparent activa tion energy for the creep deformation is estimated to be about 500 kJ/mol a t 200 MPa and 300 MPa. TEM observation for crept specimens shows that the c reep deformation is accompanied with sub-boundary formation in Mo solid sol ution phase. It is suggested that the creep deformation of the composite in the temperature range examined is interpreted in terms of the dislocation creep of Mo solid solution phase controlled by the lattice diffusion of eit her Mo or Zr.