CREEP-BEHAVIOR AND MICROSTRUCTURAL CORRELATION OF A PARTICLE-STRENGTHENED NB-1ZR-0.1C ALLOY

The steady-state creep behavior of a particle-strengthened alloy of ni obium (Nb-1Zr-0.1C) was compared with pure niobium and a Nb-1Zr alloy. The approach to a threshold stress was indicated at stress levels bel ow 16 MPa and was supported by a statistical analysis of mean particle size. Analysis of the crept microstructure showed a classic dislocati on substructure whose cell size was inversely proportional to the appl ied stress except at very low stresses. The smaller than predicted cel l size observed at low applied stresses was attributed to the particle s, preventing the dislocation cells from reaching their equilibrium di mension. Some amount of particle growth was observed which led to a re duction in creep resistance with time.