Subtask 12G1: Effects of dynamically charged helium on swelling and microstructure of vanadium-base alloys
- Argonne National Lab., IL (United States)
The objective of this work is to determine void structure, distribution, and density changes of several vanadium-base alloys irradiated in the Dynamic Helium Charging Experiment (DHCE). Combined effects of dynamically charged helium and neutron damage on density change, void distribution, and microstructural evolution of V-4Cr-4Ti alloy have been determined after irradiation to 18-31 dpa at 425-600{degrees}C in the DHCE, and the results compared with those from a non-DHCE in which helium generation was negligible. For specimens irradiated to {approx}18-31 dpa at 500-600{degrees}C with a helium generation rate of 0.4-4.2 appm He/dpa, only a few helium bubbles were observed at the interface of grain matrices and some of the Ti(O,N,C) precipitates, and no microvoids or helium bubbles were observed either in grain matrices or near grain boundaries. Under these conditions, dynamically produced helium atoms seem to be trapped in the grain matrix without significant bubble nucleation or growth, and in accordance with this, density changes from DHCE and non-DHCE (negligible helium generation) were similar for comparable fluence and irradiation temperature. Only for specimens irradiated to {approx}31 dpa at 425{degrees}C, when helium was generated at a rate of 0.4-0.8 appm helium/dpa, were diffuse helium bubbles observed in limited regions of grain matrices and near {approx}15% of the grain boundaries in densities significantly lower than those in the extensive coalescences of helium bubbles typical of other alloys irradiated in tritium-trick experiments. Density changes of specimens irradiated at 425{degrees}C in the DHCE were significantly higher than those from non-DHCE irradiation. Microstructural evolution in V-4Cr-4Ti was similar for DHCE and non-DHCE except for helium bubble number density and distribution. As in non-DHCE, the irradiation-induced precipitation of ultrafine Ti{sub 5}Si{sub 3} was observed for DHCE at >500{degrees}C but not at 425{degrees}C.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- OSTI ID:
- 415189
- Report Number(s):
- ANL/FPP/TM-287; ITER/US-95/IV-MAT-10; ON: DE96000984; TRN: 96:006511-0019
- Resource Relation:
- Other Information: PBD: Mar 1995; Related Information: Is Part Of U.S. Contribution 1994 Summary Report Task T12: Compatibility and irradiation testing of vanadium alloys; Smith, D.L. [comp.]; PB: 198 p.
- Country of Publication:
- United States
- Language:
- English
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Swelling and structure of vanadium alloys irradiated in the dynamic helium charging experiment
Subtask 12G2: Effects of dynamically charged helium on tensile properties of V-4Cr-4Ti