Modeling creep behavior of niobium silicide in-situ composites

A creep model for metal-matrix composites has been extended to treat creep in Nb-based in-situ composites containing silicides in a creeping matrix. Model calculations revealed that the creep exponent of the in-situ composites is significantly influenced by the creep behavior of the stronger reinforcement (silicide or Laves) phase. The wide range of creep exponent (1–11) observed in Nb–Ti–Hf–Si in-situ composites can be explained on the basis of the rigid or creeping behavior of the silicide (or Laves) phase during creep in the in-situ composites. The application of the creep model to designing creep-resistant microstructure for Nb-based in-situ composites is discussed in conjunction with the roles of alloy addition and Peierls–Nabarro stress in influencing the creep resistance of the in-situ composites.