Strengthening Mechanisms, Creep and Fatigue Processes in Dispersion Hardened Niobium Alloy
Final technical rept. 1 Feb 1989-31 Jan 1992
CALIFORNIA UNIV DAVIS DIV OF MATERIALS SCIENCE AND ENGINEERING
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The creep and fatigue properties of pure Nb and Nb-lZr alloy were investigated. A model was developed based on the migration of subgrain boundary that can explain the anomalous primary creep transients found in Nb-lZr alloy, due to coarsening of subgrain structure. TEM investigations confirmed that such subgrain coarsening occurs during primary creep of Nb-lZr. Baseline low cycle fatigue studies of Nb and Nb-lZr were completed. Cyclic hardening is observed and there is a microplastic plateau in Nb. The Nb-1Zr is stronger in cyclic deformation than Nb, with little influence of strain rate. The deformation in the alloy at both high and low strain rates is controlled by the interaction between gliding edge dislocation and solute atoms. Creep, fatigue, niobium alloy, dislocation mechanisms.
- Metallurgy and Metallography
- Solid State Physics