The production and annealing of point defects produced by quenching and by tensile deformation in pure gold and silver
Sharma, Ram Kishore
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https://hdl.handle.net/2142/25743
Description
Title
The production and annealing of point defects produced by quenching and by tensile deformation in pure gold and silver
Author(s)
Sharma, Ram Kishore
Issue Date
1968
Doctoral Committee Chair(s)
Koehler, James S.
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
point defect production
point defect annealing
quenching
tensile deformation
gold
silver
Language
en
Abstract
Gold specimens of six nines purity were strained at 4.Z K
by tensile deformation and were quenched from 700 ± 40 oC. For gold
deformed at 4.ZoK the most prominent annealing is observed in the
region between ZOoC and 70°C. For this case the annealing at 40°C
obeys second order kinetics and the effective energy of migration,
which increases with increasing purity, is 0.90 ± .04 eV for specimen
of highest purity. For fast quenched gold (dT/dt = 5 x 10^4
to
5 0 .00 1.1 x 10 C/sec) the stage III annea1ing occurs from 40 C to 100 C.
The annealing obeys second order kinetics and the effective energy of
migration increases from 0.80 eV to 0.90 eV as the residual resistivity
at 4.Z o K decreases from 9.5 x 10 -100 cm to 4.Z x 10 -10 0 cm. For slow
dT 3 4 0 . quenched gold (dt = 7 x 10 to Z x 10 C/sec) the annea1~ng follows
first order kinetics and the activation energy of migration is 0.70
± .04 eV. The stage III annealing in deformed and fast quenched gold
is attributed to the migration of a single vacancy in the presence of
a high density of sinks.
The results are shown to be consistent with an annealing
theory which assumes that the divacancy has a high binding energy and
that the value of sink density is important in determining the rate
limiting process for the annealing. Fr~m the annealing kinetics of
fast quenched gold and by using high temperature diffusion and thermal
equilibrium data, the binding energy of a divacancy is calculated to be
0.35 < B < 0.52 eV.
Some tensile deformation experiments were done on 99.9999%
pure silver. The annealing is found to be much more complicated as
compared with gold and stage III activation energy is 0.70 ± .04 eV.
The identity of defects taking part in stage III in silver is not
clear at the present time.
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