High temperature fully reversed fatigue tests of high purity copper were made as a function of stress amplitude. A mean cavity volume V_p and corresponding number density of cavities N_p were determined from the total cavity volume faction V_V obtained from precision density measurements (PDM) and the total cavity surface area S_V calculated from small angle neutron scattering (SANS) measurements. Under the range of stress amplitudes tested, the plastic strain rate dε_p/dt was found to cover three orders of magnitude. The results of these tests of the influence of stress amplitude on cavity growth were combined with previous results in which the frequency of cycling was varied. It was found that the cavity growth rate correlates well with the measured plastic strain and stress amplitude through the relation dV_p/dt ∝ (dε_p/dt)~(0.45) ∝ Δσ~2.
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