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A STUDY OF QUENCH-HARDENING IN SILVER.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO
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Silver wires of 10 mil diameter have been quenched from 90015C at an average quenching rate of 100000Csec. Isothermal aging kinetics have been investigated by means of room temperature 0.4 per-cent-yield-strength measurements. The incubation periods that were observed for the 300C, 400C, and 450C aging temperatures indicated that excess single vacancies formed di-vacancies and trivacancies which served as nuclei for the formation of hardening complexes. The maximum strength developed at these temperatures was 10.0 kgsq mm and it is postulated that this strength resulted from the formation of dislocation loops and stacking fault tetrahedra. The 500C and 550C aging temperatures developed a yield strength of only 7.3 kgsq mm and hardening at this aging temperature is assumed to be due to dislocation loops only. The activation energy for the 300C to 450C hardening mechanism was found to be 0.67 .03 eV. This is the activation energy associated with the migration of single vacancies. Author
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