ANSTO :: Browsing by Author "Li, HJ"

Browsing by Author "Li, HJ"

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Atomic origins of radiation-induced defects and interfacial strengthening in additively manufactured titanium aluminide alloy irradiated with Kr-ions at elevated temperature
(Elsevier, 2019-04-04) Zhu, HL; Qin, MJ; Aughterson, RD; Wei, T; Lumpkin, GR; Ma, Y; Li, HJ
The irradiation microstructure of the additively manufactured titanium aluminide (TiAl) alloy subjected to in situ transmission electron microscope (TEM) irradiation with 1 MeV Kr ions at the elevated temperature of 873K was investigated. Triangle and large hexagon shaped volume defects were observed within the γ-TiAl phase in the TEM images of the irradiated microstructure. High resolution TEM images and composition analyses revealed the volume defects were vacancy-type stacking fault tetrahedrals (SFTs). Molecular dynamic simulations showed that the increased diffusion coefficient at the elevated temperature promoted the movement and aggregation of vacancies, leading to the formation and growth of SFTs in the irradiated FCC γ phase. The lamellar interfaces in the irradiation microstructure were more effective for acting as strong sinks to absorb the primary point defects and defect clusters at the elevated temperature. The initial defects at the interfaces of the additively manufactured TiAl alloy enhanced the sink strength of the material and greatly refined SFTs near the lamellar interfaces. © 2019, The Authors.
Corrigendum to ‘Atomic origins of radiation-induced defects and the role of lamellar Interfaces in radiation damage of titanium aluminide alloy irradiated with Kr-ions at elevated temperature’ [Acta Mater. 172 (2019) 72–83]
(Elsevier, 2020-09-15) Zhu, HL; Qin, MJ; Aughterson, RD; Wei, T; Lumpkin, GR; Ma, Y; Li, HJ
The authors regret that the scale bars in Figure 8(c) BF-STEM and 8(d) HAADF-STEM for volume defects near the γ/γ lamellar interfaces in the Kr-ion irradiated microstructure of the TiAl alloy irradiated at 873 K are mislabelled. The authors would like to apologise for any inconvenience caused. © 2020 Acta Materialia Inc. Published by Elsevier Ltd.
Deformation mechanisms of twinning-induced plasticity steels: in situ synchrotron characterization and modeling
(Elsevier, 2010-03) Yan, K; Carr, DG; Callaghan, MD; Liss, KD; Li, HJ
The plastic deformation behavior of twinning-induced plasticity steels of composition Fe-25Mn-3Si-3Al are investigated by means of in situ synchrotron high-energy X-ray diffraction and compared to self-consistent simulations. It is the first time the alternating interaction of {1 1 1} <1 1 0> slip and {1 1 1} <1 1 2> twinning have been directly observed in situ while undergoing uniaxial tension. The deformation texture is determined mainly by dislocation gliding, while deformation twinning impedes the reinforcement of texture. © 2010, Elsevier Ltd.
Development of a new powder-bed arc additive manufacturing approach for producing high entropy alloys
(Materials Australian and The Australian Ceramic Society, 2022-06-01) Dong, BS; Wang, ZY; Pan, Z; Li, HJ
High entropy alloys (HEAs) have gained significant attention over the past decade from both academic and industrial communities due to their unique design concept and promising properties. The manufacturing of this emerging material with desired properties remains challenging. A new powder-bed arc additive manufacturing (PAAM) has been developed at the University of Wollongong for producing HEAs. This approach, with a high level of flexibility for controlling the forming process and the characteristic rapid solidification, enables the tailoring of the microstructure through the process control and the effective reduction of the chemical segregation in these compositionally complexed alloys. Additionally, compared with the laser and electron beam based additive manufacturing, PAAM is advantageous for higher production rate hence it is promising in industrial applications for producing bulk components in shorter period. The production of a eutectic AlCoCrFeNi2.1 HEA using this new PAAM approach will be presented to demonstrate its capability. Then, the FeCr0.4V0.3Ti0.2Ni1.3 HEA with low neutron cross-section is successfully designed and fabricated in this system. The good tensile properties of this novel HEA make it become a potential candidate as a structural material in the future nuclear industry.
Development of a new powder-bed arc additive manufacturing approach for producing high entropy alloys
(Australian Nuclear Science and Technology Organisation, 2021-11-26) Dong, BS; Muránsky, O; Zhu, Hl; Muránsky, O; Wang, ZY; Reid, M; Li, HJ
High entropy alloys (HEAs) have gained significant attention over the past decade from both academic and industrial communities due to their unique design concept and promising properties. The manufacturing of this emerging material with desired properties remains challenging. Most of previous work utilized conventional vacuum arc melting and casting methods for producing HEAs. However, the disadvantage of typical casting microstructure, columnar dendrite and serious chemical segregation, causes serious deterioration to their mechanical properties. A new powder-bed arc additive manufacturing (PAAM) has been developed at the University of Wollongong for producing HEAs. This approach, with a high level of flexibility for controlling the forming process and the characteristic rapid solidification, enables the tailoring of the microstructure through the process control and the effective reduction of the chemical segregation in these compositionally complexed alloys. Additionally, compared with the laser and electron beam based additive manufacturing, PAAM is advantageous for higher production rate hence it is promising in industrial applications for producing bulk components in shorter period. The production of a eutectic AlCoCrFeNi2.1 HEA using this new PAAM approach will be presented to demonstrate its capability. The characterisation work shows that the produced AlCoCrFeNi2.1 samples have a lamellar microstructure consisting of the soft but ductile face-centered cubic (FCC) phase as well as the hard body-centered-cubic (BCC) phase. The material demonstrates a remarkable combination of excellent ultimate tensile strength (719 MPa) and ductility (elongation ~27%). The current work has demonstrated that the developed PAAM process is promising for producing HEA components with desired properties. © The Authors
Direct, time-resolved in-situ observation of dynamic recyrstallization and related phenomena in the bulk of zirconium alloy
(Australian Institute of Physics, 2009-02-04) Liss, KD; Garbe, U; Schambron, T; Almer, JD; Li, HJ; Yan, K; Dippenaar, RJ
Not available
Effect of stainless steel can/glass-ceramic interaction layer on aqueous durability
(Materials Research Society, 2007) McGlinn, PJ; Zhang, YJ; Li, HJ; Payne, TE
Calcined high-level radioactive waste (HLW) stored at the Idaho National Laboratory (LNL) will eventually be immobilised in a suitable wasteform before disposal. A tailored glass-ceramic wasteform, produced by hot isostatic pressing (HIPing) in stainless steel (SS) cans, has been developed at the Australian Nuclear Science & Technology Organisation (ANSTO) as a costsaving alternative to glass which would improve waste loading and density, and reduce waste volume. We have studied the SS/wasteform interactions under HIPing conditions to understand whether such interactions would have any detrimental effect on long-term wasteform stability. This has been demonstrated by carrying out aqueous durability tests, under near-neutral and alkaline conditions, on the wasteform at the interaction layer, and on the wasteform distal to this reaction edge. Reaction during HIPing resulted in verifiable Cr diffusion from the can wall into the wasteform, yet without any detectable detrimental impact on the HIP can or the aqueous durability of the wasteform. © 2007 Materials Research Society.
Effect of welding thermal cycle on the microstructure of Zircaloy-4
(International Institute of Welding, 2009-07-16) Thorogood, KJ; Li, HJ; Carr, DG; Harrison, RP; Nolan, D
Zirconium and its alloys are important materials commonly utilised in the nuclear industry, primarily due to their low neutron absorption cross-section and excellent corrosion resistant properties. Zircaloy-4 is one of the most widely used nuclear grade zirconium alloys and contains primary alloying elements of tin, iron, chromium and oxygen. Typical applications include structural core components and fuel cladding. Fully welded structures such as heavy water reflector vessels have been fabricated from Zircaloy-4. Although the structure-property relationships of Zircaloy-4 parent metal and weld metal is well understood, there is limited understanding of the same relationship for the narrow weld heat-affected zone. The work reported in this paper is an investigation of the influence of the weld thermal cycles on the microstructure and texture of Zircaloy-4 heat-affected zone material. Discrete regions within the heat-affected zone were simulated using a thermo-mechanical simulator (Gleeble 3500). Peak temperatures of the thermal cycles studied were 1000,1200, 1400 and 1600°C. Weld simulation has been shown to produce a volume of material sufficient for analysis and which represents the individual sub-zones. © 2010, International Institute of Welding
Effects of post heat treatment on the microstructure and mechanical properties of wire arc additively manufactured Hastelloy C276 alloy
(Elsevier, 2021-07) Qiu, ZJ; Wu, BT; Wang, ZY; Wexler, D; Carpenter, K; Zhu, HL; Muránsky, O; Zhang, JR; Li, HJ
Post-processing is often inevitable for most additively manufactured components in order to improve material properties and product quality. In this study, the influence of post-heat treatments (PHTs) at 871 °C and 1177 °C on the microstructure and mechanical properties of a nickel-base Hastelloy C276 alloy prepared using wire arc additive manufacturing (WAAM) were investigated. The results showed that after a PHT at 871 °C, the as-built alloy was strengthened due to the formation of a large amount of Mo-rich nano-sized μ phase in the interdendritic areas. This was at the expense of a significant ductility loss. In contrast, no μ phase precipitates were observed after PHT at 1177 °C. Furthermore, the 1177 °C treatment led to the dissolution of the Mo-rich p phase which was present in the as-built sample, increased solid-solution strengthening, and improvements in both strength and ductility concurrently. This study enables an improved understanding of post-processing-microstructure-property inter-relationships for Hastelloy C276 alloy prepared by WAAM, providing guidelines for further microstructure optimization through PHT to improve the material's mechanical properties. © 2021 Elsevier Inc.
Energy-based approach for the evaluation of low cycle fatigue behaviour of 2.25Cr-1Mo steel at elevated temperature
(Elsevier, 2010-08-20) Callaghan, MD; Humphries, SR; Law, M; Ho, M; Bendeich, PJ; Li, HJ; Yeung, WY
The energy-based approach for the evaluation of low cycle fatigue behaviour of 2.25Cr–1Mo steel at elevated temperature has been investigated and detailed analyses discussed. Plastic strain energy was determined per cycle and found to characterise both crack initiation and propagation to failure regimes. At cyclic stabilisation, average plastic strain energy may be used as a suitable damage parameter and correlations between experimental and predicted data determined. The fatigue toughness to failure of the material was established and the development of a fatigue toughness to crack propagation analysis is presented. © 2010, Elsevier Ltd.
Evaluation of high temperature fatigue behaviour of P22 by miniature specimen testing
(Trans Tech Publications, 2010-01-01) Callaghan, MD; Humphries, SR; Law, M; Li, HJ; Yeung, WY
Miniature specimen testing to evaluate mechanical properties, presents a novel opportunity to undertake structural integrity assessments of in-service power generation components, by removing only a very small volume of material. In this study, high temperature fatigue testing of P22 steel was undertaken and a number of fatigue properties determined using a miniature specimen testing methodology. Good comparisons were observed between fatigue properties determined by miniature specimens and the more established standard-sized specimen testing reported in literature.
From single grains to texture
(Wiley-VCH Verlag GmbH & Co. KGaA, 2009-10) Yan, K; Liss, KD; Garbe, U; Daniels, JE; Kirstein, O; Li, HJ; Dippenaar, RJ
Structural materials, such as metals, ceramics, and their composites are most often polycrystalline. The nature, morphology, and composition of their microstructure determine in large measure the mechanical properties of the final product, and the art to design novel materials is to find particular arrangements which make them harder, more shock absorbing, heat resistant, or self-recovering upon damage and aging. The understanding of the basic processes and their interplay in a polycrystalline structure are most important for improved simulation of plastic deformation and to predict their thermo-mechanical behavior. © 2009, Wiley-VCH Verlag GmbH & Co. KGaA
Hydride precipitation and its influence on mechanical properties of notched and unnotched Zircaloy-4 plates
(Elevier Science BV., 2013-05-01) Wang, ZY; Garbe, U; Li, HJ; Harrison, RP; Toppler, K; Studer, AJ; Palmer, T; Planchenault, G
The hydride formation and its influence on the mechanical performance of hydrided Zircaloy-4 plates containing different hydrogen contents were studied at room temperature. For the unnotched plate samples with the hydrogen contents ranging from 25 to 850 wt. ppm, the hydrides exerted an insignificant effect on the tensile strength, while the ductility was severely degraded with increasing hydrogen content. The fracture mode and degree of embrittlement were strongly related to the hydrogen content. When the hydrogen content reached a level of 850 wt. ppm, the plate exhibited negligible ductility, resulting in almost completely brittle behavior. For the hydrided notched plate, the tensile stress concentration associated with the notch tip facilitated the hydride accumulation at the region near the notch tip and the premature crack propagation through the hydride fracture during hydriding. The final brittle through-thickness failure for this notched sample was mainly attributed to the formation of a continuous hydride network on the thickness section and the obtained very high hydrogen concentration (estimated to be 1965 wt. ppm). © 2013, Elsevier Ltd.
Hydrogen-induced microstructure, texture and mechanical property evolutions in a high-pressure torsion processed zirconium alloy
(Elsevier Ltd., 2012-11-01) Wang, ZY; Garbe, U; Li, HJ; Studer, AJ; Harrison, RP; Callaghan, MD; Wang, Y; Liao, XZ
The gaseous hydriding-induced evolutions of the microstructure, texture and mechanical properties of Zircaloy-4 processed by high-pressure torsion (HPT) were assessed. Much delta-ZrH(1.66) precipitation at 15 atm (21%) incurred significant hardening of vacuum-annealed HPT samples, and pure epsilon-ZrH(2) obtained at 20 atm showed a superior microhardness of 470 HV(0.3) and a low fracture toughness of 0.63 MPa m(1/2). The delta-hydrides presented strong (1 1 1) texture and followed the (0 0 0 1)(alpha-Zr)//{1 1 1}(delta-ZrH1.66) orientation relationship with the alpha-Zr matrix. During hydriding, alpha-Zr recrystallization texture was developed from the initial deformation texture. Copyright © 2012 Acta Materialia Inc.
In situ observation of dynamic recrystallization in the bulk of zirconium alloy
(Wiley-VCH Verlag Berlin, 2009-08) Liss, KD; Garbe, U; Li, HJ; Schambron, T; Almer, JD; Yan, K
Dynamic recrystallization and related effects have been followed in situ and in real time while a metal undergoes rapid thermo-mechanical processing. Statistics and orientation correlations of embedded/bulk material grains were deduced from two-dimensional X-ray diffraction patterns and give deep insight into the formation of the microstructure. Applications are relevant in materials design, simulation, and in geological systems. © 2009, Wiley-VCH Verlag Berlin
Industrial application experiments on the neutron imaging instrument DINGO
(Elsevier, 2017-01-01) Garbe, U; Ahuja, Y; Ibrahim, R; Li, HJ; Aldridge, LP; Salvemini, F; Paradowska, AM
The new neutron radiography / tomography / imaging instrument DINGO is operational since October 2014 to support the area of neutron imaging research at ANSTO. The instrument is designed for a diverse community in areas like defense, industrial, cultural heritage and archaeology applications. In the field of industrial application it provides a useful tool for studying cracking and defects in concrete or other structural material. Since being operational we gathered experience with industrial applications and commercial customers demanding beam time on DINGO. The instrument is a high flux facility with is 5.3 × 107 [n/(cm2s)] (confirmed by gold foil activation) for an L/D of approximately 500 at HB-2. A special feature of DINGO is the in-pile collimator position in front of the main shutter at HB-2. The collimator offers two pinholes with a possible L/D of 500 and 1000. A secondary collimator separates the two beams by blocking one and positions another aperture for the other beam. The neutron beam size can be adjusted to the sample size from 50 × 50 mm2 to 200 × 200 mm2 with a resulting pixel size from 27 μm to ∼100 μm. The whole instrument operates in two different positions, one for high resolution and one for high speed. We would like to present our first experience with commercial customers, scientific proposals with industrial applications and how to be customer ready. © 2017 The Author(s). Published by Elsevier B.V.
Investigation of residual stresses in titanium aerospace components formed via additive manufacturing
(Engineers Australia, 2014-01-01) Hoye, N; Li, HJ; Cuiuri, D; Paradowska, AM; Thorogood, KJ
In the present study gas tungsten arc welding (GTAW) with automated wire addition was used to additively manufacture (AM) a representative thin-walled aerospace component from Ti-6Al-4V in a layer-wise manner. Residual strains, and hence stresses, were analysed quantitatively using neutron diffraction techniques on the KOWARI strain scanner at the OPAL research facility operated by the Australian Nuclear Science and Technology Organisation (ANSTO). Results showed that residual strains within such an AM sample could be measured with relative ease using the neutron diffraction method. Residual stress levels were found to be greatest in the longitudinal direction and concentrated at the interface between the base plate and deposited wall. Difficulties in measurement of lattice strains in some discrete locations within the deposited material were ascribed to the formation of localised grain orientation where α-Ti laths form in aligned colonies within prior β-Ti grain boundaries upon cooling. Neutron diffraction measurements of residual stress were cross-correlated using the contour method with results found to be in close agreement. Observations of microstructure reveal 'basket-weave' morphology typical of fusion welds in Ti-6Al-4V. Microhardness measurements show lower hardness in the deposited material compared to the base plate and a further small decrease in hardness in the top region of the deposit, indicating a dependence on thermal cycling from sequential weld deposition. © 2021 Informit
Low neutron cross-section FeCrVTiNi based high-entropy alloys: design, additive manufacturing and characterization
(OAE Publishing, 2022-01-13) Dong, BS; Wang, ZY; Zhu, HL; Muránsky, O; Qiu, ZJ; Shen, C; Pan, ZX; Li, HJ
The development of high-entropy alloys (HEAs) based on the novel alloying concept of multi-principal components presents opportunities for achieving new materials with desired properties for increasingly demanding applications. In this study, a low neutron cross-section FeCrVTiNi-based HEA was developed for potential nuclear applications. A face-centred cubic (FCC) HEA with the nominal composition of FeCr0.4V0.3Ti0.2Ni1.3 is proposed based on the empirical thermodynamic models and the CALculation of PHAse diagrams (CALPHAD) calculation. Verifications of the predictions were performed, including the additive manufacturing of the proposal material and a range of microstructural characterizations and mechanical property tests. Consistent with the prediction, the as-fabricated HEA consists of a dominant FCC phase and minor Ni3Ti precipitates. Moreover, significant chemical segregation in the alloy, as predicted by the CALPHAD modelling, was observed experimentally in the produced dendritic microstructure showing the enrichment of Ni and Ti elements in the interdendritic regions and the segregation of Cr and V elements in the dendritic cores. Heterogenous mechanical properties, including microhardness and tensile strengths, were observed along the building direction of the additively manufactured HEA. The various solid solution strengthening effects, due to the chemical segregation (in particular Cr and V elements) during solidification, are identified as significant contributing factors to the observed mechanical heterogeneity. Our study provides useful knowledge for the design and additive manufacturing of compositionally complex HEAs and their composition-microstructure-mechanical property correlation. © The Author(s) 2022
Martensitic phase transformation and deformation behavior of Fe–Mn–C–Al twinning-induced plasticity steel during high-pressure torsion
(Wiley Online Library, 2014-02-05) Yan, K; Bhattacharyya, D; Lian, Q; Kabra, S; Kawasaki, M; Carr, DG; Callaghan, MD; Avdeev, M; Li, HJ; Wang, Y; Liao, XZ; Langdon, TG; Liss, KD; Dippenaar, RJ
The transformation between the face centered cubic austenitic and hexagonal close-packed martensitic phases during high-pressure torsion processing was observed in a Fe–Mn–C–Al twinning-induced plasticity steel. This phase transformation was not found in the same material processed by unidirectional compressive and tensile deformation. Initiated by the high-pressure loading, the martensite phase initially increased with torsional strain but diminished subsequently. Texture evolution of the austenitic phase was compared with the ideal texture distribution of face-centered cubic materials after shear deformation.© 2014, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Measurement of residual stresses in titanium aerospace components formed via additive manufacturing
(Trans Tech Publications Ltd, 2014-02) Hoye, N; Li, HJ; Cuiuri, D; Paradowska, AM
In the present study gas tungsten arc welding (GTAW) with automated wire addition was used to additively manufacture (AM) a representative thin-walled aerospace component from Ti-6Al-4V in a layer-wise manner. Residual strains, and hence stresses, were analysed quantitatively using neutron diffraction techniques on the KOWARI strain scanner at the OPAL research facility operated by the Australian Nuclear Science and Technology Organisation (ANSTO). Results showed that residual strains within such an AM sample could be measured with relative ease using the neutron diffraction method. Residual stress levels were found to be greatest in the longitudinal direction and concentrated at the interface between the base plate and deposited wall. Difficulties in measurement of lattice strains in some discrete locations were ascribed to the formation of the formation of localised texturing where α-Ti laths form in aligned colonies within prior β-Ti grain boundaries upon cooling. Observations of microstructure reveal basket-weave morphology typical of welds in Ti-6Al-4V. Microhardness measurements show a drop in hardness in the top region of the deposit, indicating a dependence on thermal cycling from sequential welds. © 2014, Trans Tech Publications.

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