THE MICROSTRAIN REGION IN HIGH-PURITY REFRACTORY METALS.
Quarterly rept. no. 2, 1 Jun-31 Aug 66.
FRANKLIN INST RESEARCH LABS PHILADELPHIA PA
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It is shown that the hydrogen annealing treatmets described in AD-639 603 which are required in the preparation of molybdenum single crystals suitable for dislocation velocity experiments leave the remaining dislocations in an unpinned state. Some tentative dislocation velocity determinations are presented leading to an activation volum v approx 20b to the third power in agreement with values of v 15b to the third power found by strain-rate change experiments in the macro-strain region. The micro-strain behavior of molybdenum single crystals treated in hydrogen in a similar fasion is examined. The true elastic limit tau sub E. the dissipative friction stress tau sub F, and the activation volume v are found to be tau sub E 0.07 plus or minus 0.0002 Kgsq, tau sub F 0.04 plus or minus Kgsq mm and v approx 1700b to the third power. These results are compared to those obtained with as zone-refined crystals. Author
- Properties of Metals and Alloys