Browsing by Author "Munroe, P"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- ItemRelationship between damage and hardness profiles in ion irradiated SS316 using nanoindentation–experiments and modelling(Elsevier, 2016-11) Saleh, M; Zaidi, Z; Hurt, C; Ionescu, M; Short, KT; Daniels, JE; Bhattacharyya, D; Munroe, P; Edwards, LIn this work, the authors apply the “top-down” nanoindentation testing method to assess the mechanical property changes in ion-irradiated metallic alloys for three different ion energies in order to understand the relationship between ion energy, damage peak depth and hardness peak depth. The samples were irradiated with He+2 ions having 1, 2 and 3 MeV beam energies respectively. The curves for ΔH (radiation induced hardness) have been obtained by calculating the difference of the irradiated and unirradiated hardness curves after these were corrected for indentation size effect. Three-dimensional analytical and numerical models have been developed to obtain greater insight into the mechanisms involved in the nanoindentation processes, the nature of the plastic zone, and how these affect the hardness results, including the full hardness profiles with respect to depth. This is particularly valuable in situations where the damage profile is non-uniform, as in the present case, and provides the means to predict expected hardness peak positions and values for a given irradiation dose. Copyright © 2017 Elsevier B.V.
- ItemStress/strain induced flux pinning in highly dense MgB2 bulks(Institute of Electrical and Electronics Engineers (IEEE), 2009-06-01) Zeng, R; Dou, SX; Lu, L; Li, WX; Poh, CK; Kim, JH; Horvat, J; Shi, DQ; Wang, JL; Munroe, P; Wang, XF; Zheng, RK; Ringer, SP; Rindfleisch, M; Tomsic, MWe have systematically studied the flux pinning behavior of MgB(2) bulks synthesized by direct diffusion of Mg into pressed pellets of high purity crystalline B powder, with and without mixing with C and SiC nanoparticles, at a reaction temperature of 850 degrees C for 10 hrs. All of the samples showed very high purity and high density, but their microstructure and flux pinning behavior showed significant differences. It was found that the pure MgB(2) agrees with the delta T(c) pinning model, nano-C doped MgB(2) agrees with the delta l pinning model, while the SiC + MgB(2) composite agrees with the delta epsilon pinning model (stress/strain field pinning), since the dominant micro-defects that influence the flux pinning in these three samples are different. © 2009, Institute of Electrical and Electronics Engineers (IEEE)
- ItemStudies of high dpa ion beam irradiation effects on fcc AA-6061 and fcc-bcc duplex steel 2205: micromechanical modelling and nano-indentation examination of hardness variations(Karlsruhe Institute of Technology, 2015-05-10) Saleh, M; Munroe, P; Short, KT; Edwards, LThe irradiation effects of high dpa and the ramification on the engineering assessment of reactor components in GEN IV systems is of considerable interest. Most polycrystalline metallic materials derive their strengths from the interactions of dislocations with defects such as solid solution alloying elements, interstitial elements, other dislocations, grain boundaries and sub-microscopic precipitates. Irradiation of metals and alloys at temperatures below those that anneal their defects typically produces pronounced radiation hardening, this is investigated herein to better understand the application of complex alloys in future reactor systems. . The current study focuses on ion beam irradiation of AA6061 and Duplex steel 2205, utilising the ANATRES Accelerator at ANSTO with 12 MeV Au+5 ions used as the irradiating ions. To induce a 100 dpa damage, often cited as the operating level of GEN IV reactor, heavy Au+5 ions are necessary as self-ion irradiation would fail to induce the required damage. The main attribute of ion irradiation is the rapid accumulation of end of life doses over a short duration.. Conversley, neutron irradiation experiments in thermal test reactors may accumulate damage at a rate of 3–5 dpa year, e.g. the ANSTO OPAL reactor with 20 MW is capable of 100 MeV with reactor face neutron thermal flux of 4.0E10 n/cm2/s thus resulting in a less than optimal 2 dpa per year. A key question still exits between the complementarity of neutron and ion irradiation with respect to the nature of damage, size, density and distribution of dislocation loops; black dots; and the extent of the dislocation networks. Although the same number of displacements can be produced using ion irradiation, there are differences in spatial defect distribution between thes e teh two. The post-irradiation measurements in effect quantify the final state of damage and the neutron-ion equivalence without an evaluation of the damage path. The simulation code Stopping and Range of Ions in Materials (SRIM) is used to model the irradiation process and compute the initial required experimental flux. Post irradiation studies of the micromechanical behaviour are done through nano-indentation (to a depth of 300 nm) using a diamond Berkovich tip. This allows for estimates of moduli and relative estimates of the strengths and hardening of individual phases and individual grains within a multiphase alloy. The results show a marked increase in the hardening of AA 6061 with a more modest increase in the Duplex steel 2205. Coupling these results to micromechanical FEA and crystal plasticity modelling, the authors hope to better describe the role of multi-scale modelling in complementing micromechanical testing and the extrapolation of results for engineering assessment.
- ItemStudies of high dpa ion beam irradiation fcc-bcc duplex steel 2205: micromechanical testing and nanoindentation examination of hardness variations(The Minerals, Metals & Materials Society, 2020-02-26) Saleh, M; Xu, A; Munroe, P; Bhattacharyya, DNot available.