... dpa radiation damage point defects vacancy interstitial dislocation loops cavities climb M. Grif ths1 Journal of ASTM International, Vol. 5, No. 1 Paper ID JAI101146 Available online at www.astm.org Microstructure Evolution in Zr Alloys during Irradiation: Dose, Dose Rate, and Impurity...

... of the radiation damage that forms in Zr alloys will be illustrated and discussed in terms of the dose, dose rate, and impurity factors that are applicable. zirconium irradiation fast neutron flux dpa radiation damage point defects vacancy interstitial dislocation loops cavities climb M. Grif...

... microscopy (TEM). The irradiation of copper with 600 MeV protons yields an average recoil energy of 2.3 MeV, giving rise to concurrent production of multi displacement cascades and helium (125 atomic part per million/displacement per atom) atoms. The TEM investigation showed a complete absence of cavity...

... porosity and on the development of small phase-boundary gas bubbles that can act as void nuclei. Calculations for the evolution of phaseboundary fission-gas bubbles show that such bubbles provide critical cavity sizes (i.e., the size above which the cavity will grow by bias-driven vacancy flux) consistent...

... segregation loops cavities Stanley B. Fisher, ~Vincent M. Callen, 1and PatrMa K. Rose ~ Microstructural Characterization of Irradiated Nimonic PE16 REFERENCE: Fisher, S. B., Callen, V. M., and Rose, P. K., "Microstructural Characterization of Irradiated Nimonie PEI6," Effects ofRadiation on Materials...

... information on the various aspects of the kinetics of the cavitation process without involving any assumptions. Stereology cavities voids creep kinetics quantitative microscopy Arun M. Gokhale UTILITY OF STEREOLOGICAL MEASUREMENTS IN THE STUDY OF CREEP CAVITATION KINETICS REFERENCE: Gokhale A.M...

... the presence of precipitates; they are: helium collection at matrix-precipitate interfaces, point-defect collection at matrix-precipitate interfaces, the interface energy credit due to the coupled growth of a cavity-precipitate pair and possible local bias effects due to matrix-precipitate interface strains...

... production rate, the width of the cavity denuded zone, and the cavity sink strength in the grain interior. The calculated accumulation of helium is in good agreement with the measured gas content of grain boundaries in aluminum, PE 16, and 316 stainless steel. The flux of helium to grain boundaries increases...

... to the total nucleation rate increases with temperature. The results confirm the important role of transmutant helium in promoting void swelling. cavities helium effects radiation damage void nucleation void swelling Roger E. Stoller^ and G. Robert Odette^ A Comparison of the Relative Importance...

... ++ ions. The specimens contained a bimodal cavity distribution consisting of a population of larger cavities (average radius 7.6 nm) and a population of smaller cavities (average radius 1.2 nm). The upper cut-off of the cavity radii for the smaller cavities, 2.5 nm, is interpreted as r c c...

... It has been shown theoretically that bias-driven cavity swelling can only occur after either a critical cavity radius has been achieved or a critical number of gas atoms has been accumulated in a cavity. These possibilities merge into each other, as increasing the contained gas lowers...

..., air, He-4CH 4 and He-3SO 2 . Crack growth in all cases was intergranular and involved the nucleation and growth of micrometre-sized cavities on the grain boundaries. The air and He-3SO 2 environments were very aggressive, increasing the crack growth rates over those in helium by more than 100-fold...

... creep mechanism diffusion-accommodated flow creep models electron microscopy grain boundary diffusion volume diffusion cavities faulted dislocation loops SIPA 12 J, Mc Beeston and L, Eo Thomas 71 CREEP AND SWELLING OF TYPE 348 STAINLESS STEEL AT TEMPERATURES UP TO 700 K AND COMPARISON...

... of suppression increased with increasing amounts of preinjected helium. The uninjected sample areas contained a unimodal distribution of cavities, including the largest cavities observed. A bimodal cavity distribution containing a large number density of small cavities and a smaller number density of larger...

... temperatures of 420 K. The helium content ranges from 10–1000 at. ppm. Helium-containing and helium-free specimens were irradiated with neutrons at 940 K to 1.4 × 10 25 and 4.8 × 10 25 n.m −2 (E > 0.1 MeV). Preimplantation with helium had essentially no effect on cavity size, concentration and volume...

...) or that of 60s beam on/ 60s beam off (slow pulse). In the case of no He injection, the pulse irradiation suppressed completely the formation and growth of cavities at the irradiation temperature of 1023K. For the case of He preinjection at the higher irradiation temperatures, the pulse irradiation restrained...

... The theory of cavity nucleation in irradiated metals has been modified to include three important effects: (1) non-ideality of the inert gas in cavities, (2) a linearly increasing helium concentration with dose, and (3) nucleation of cavities on approximately equilibrium bubbles of any size...

...). Microstructural evaluation by transmission electron microscopy revealed that, although cavity number density and average size are dependent upon the bombardment mode, total swelling is not. Peak swelling was observed at 600 and 650°C (1112 and 1202°F) for SA and CW material, respectively, with changes in swelling...

..., the rate-theory formulation does not include a cavity nucleation model; hence cavity densities obtained from experiments with preinjection of gas before heavy ion irradiation are traditionally input to the model. Furthermore, swelling is known to be sensitive to cavity densities and no values are presently...

... at a temperature of about 55°C. The alloy displayed up to 2.5 percent swelling due mainly to a precipitate of transmutation-produced silicon of which more than 6 weight percent was formed. Some cavities were also observed. Tension tests in the temperature range 55 to 200°C showed radiation-induced increases...