Recovery of Creep-Resistant Substructure in Vacuum Reduced Rutile Under Zero Reduced Stress.
IOWA STATE UNIV AMES ENGINEERING RESEARCH INST
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The recovery of creep-resistant substructure of rutile in a vacuum of .00005 torr, has been studied at temperatures of 1000, 1020, and 1040C. Compressive specimens were crept under a stress of sigma sub o 3000 psi to a strain of epsilon sub c 0.051 early in the secondary state of creep, and then allowed to recover for varying periods of time under a reduced stress of sigma sub r 300 psi. Recovery was detected by the increased creep strain which occurred upon reapplication of sigma sub o. Experimental evidence supports the model that the recovery mechanism involves the sweeping out of dislocation barriers within the material by the migration of dislocation walls or sub-boundaries. The results indicate that the recovery of creep-resistant substructure under reduced stress is the same in air and in a vacuum, but the recovery process involving creep at constant stress would be different.
- Ceramics, Refractories and Glass