Browsing by Author "Ripley, MI"

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    Investigation of reference samples for residual strain measurements in a welded specimen by neutron and synchrotron x-ray diffraction
    (Elsevier, 2006-11-15) Paradowska, AM; Finlayson, TR; Price, JWH; Ibrahim, R; Steuwer, A; Ripley, MI
    In this research, both neutron and synchrotron X-ray diffraction techniques have been used to investigate variations in measured d spacing in two reference samples. The reference “stress-free” samples, a set of cubes and a comb sample, were produced using electro-discharge machining (EDM) to obtain a macro-strain-relieved condition. It is shown that there is a variation in microstructure across the parent metal, heat-affected zone (HAZ) and weld metal. A study of the issues in using the cubes and comb sample to provide reference d0 values for the measurement of residual stress in welding is presented. © 2006 Elsevier B.V.
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    Investigation of residual stress in multi-bead on plates
    (Australian Institute of Physics, 2006-02-07) Paradowska, AM; Price, JWH; Finlayson, TR; Ibrahim, R; Belvins, R; Ripley, MI
    The neutron diffraction technique is used to investigate and compare the residual stress characteristics in fully restrained samples with different numbers of beads. The aim of the research was to characterize the residual stress distribution which arises in a welded component with increasing the number of passes or beads. These results support the concept that welding integrity can be increased as additional layers of welding are added
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    Investigation of strain-free reference for residual strain measurements in a weldments by neutron and synchrotron diffraction
    (Elsevier B. V., 2005-11-27) Paradowska, AM; Finlayson, TR; Price, JWH; Ibrahim, R; Steuwer, A; Ripley, MI
    The measurement of residual strain using diffraction techniques relies on the determination of a change in lattice parameter relative to reference or 'strain free' lattice parameter. Elucidating a relevant reference lattice parameter is the most important part of any diffraction-based, residual strain experiment. In this research, neutron and synchrotron diffraction techniques have been used to investigate the strain distribution in strain reference samples used to establish the residual stresses due to welding. It is shown that there is a variation in measured diffraction angles along the length of the weld, in particular for a parent metal, heat-affected zone (HAZ) and weld metal. The stress-free samples, cuboid and a comb sample, were produced A study of the issues in using the cubes and comb sample, were produced using electro-discharge maching (EDM) to obtain a macro-strain relieved condition and reveal information about microstructural and intergranular strain variations, residual stress in welding is presented. A study is presented of the application of a strain-free cuboid and a comb sample in the flux-cored arc welding (FCAW) process
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    Measurement of fracture toughness of hydrided Zircaloy - 4.
    (The Institute of Materials Engineering Australasia Ltd., 2004) Callaghan, MD; Yeung, WY; Ripley, MI; Carr, DG
    Zircaloy-4 is a zirconium alloy that will be used for construction of many of the core components in the replacement research reactor at Lucas Heights. The fracture toughness of the alloy and its radiation-induced reduction over the 40 year planned life of the reactor is an important mechanical property for this application. This study aims to simulate the radiation-induced reduction in fracture toughness by hydriding Zircaloy-4. A range of fracture toughnesses is required to calibrate the sub-size Charpy and small punch (SP) surveillance specimens that will be irradiated over the life of the reactor against standard J1C fracture toughness specimens. Pieces of Zircaloy-4 plate were hydrided in a vessel at a temperature of 520°C, at different pressures for either 10 or 22 hours. Final hydrogen concentrations between 25 wt% ppm and 380 wt% ppm hydrogen were obtained under gaseous atmosphere. The fracture toughness of the hydrided Zircaloy-4 was assessed using sub-size 2.5 mm-thick Charpy, three-point bend J1C and SP tests. The results were correlated to determine the relationship between the J-integral fracture toughness, Charpy impact energy and equivalent fracture strain (εqf) from the SP tests. It was found that as hydrogen concentration and hydride formation increased, the fracture toughness of the alloy generally decreased. The results show there to be a useful relationship between fracture toughness and εqf measured for the SP tests.
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    Neutron diffraction studies of advanced tool steels
    (The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Doyle, ED; Wong, YC; Ripley, MI
    Martensitic stainless steels, based around AISI 420 grade, are being increasingly specified for the production of small to medium sized moulds, which are used to manufacture high value-added plastics components for use in the automotive and food packaging industries. However, the increasing complexity of modern die design is leading to an increased incidence of mould failure due to (a) fracture as a consequence of the build-up of high residual stresses during heat treatment and (b) stress corrosion cracking in water channels. The response of the international steel industry has been to introduce modified grades of AISI 420 to overcome these problems. However, there have been no reports to date of the effect of such modification on the generation of residual stress as a function of key heat treatment parameters. ln the present study, neutron diffraction was used to identify the bulk residual stress distribution as a function of the quench rates in high pressure vacuum heat treatment for two different grades of AISI 420. Details of the results plus their analysis in terms of hardenability of the steels will be presented and discussed in the paper. © 2005 The Authors
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    Radiation-induced growth in zircaloy-4
    (International Group On Research Reactors, 2005-09-12) Harrison, RP; Carr, DG; Kim, YS; Boccanera, L; Ripley, MI; Stathers, PA; Humphries, SR
    Not available
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    Residual stress measurements by neutron diffraction in multi-bead welding
    (Elsevier, 2006-11-15) Paradowska, AM; Price, JWH; Ibrahim, R; Finlayson, TR; Blevins, RJ; Ripley, MI
    The neutron diffraction technique is used to investigate and compare the residual stress characteristics in fully restrained samples with different numbers of beads. The aim of the research was to characterize the residual stress distribution which arises in a welded component with increasing the number of passes or beads. The resolution of the measurements carried out in this work achieves a new level of detail and reveals significant features of the residual stress pattern in multi-bead welding. The findings have important consequences for the design of welding procedures, demonstrating the effects of placing new beads on prior welding. © 2006 Elsevier B.V.
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    Residual stress measurements by neutron diffraction in welded steel structures
    (The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Paradowska, AM; Price, JWH; Finlayson, TR; Ibrahim, R; Blevins, RJ; Ripley, MI
    In this paper the neutron diffraction technique is used to investigate and compare the residual stress characteristics due to various restraints for a single bead and in fully restrained samples with different numbers of beads. The aim of the research was to characterize the residual stress distribution which arises in a welded component with increasing the number of passes. The care and resolution of the measurements carried out in this work achieves a new level of detail and reveals significant features of the residual stress pattern in multi-bead welding. The findings have important consequences for the design of welding procedures, and fitness-for-purpose assessments. © The Authors
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    Residual stresses in a cast iron automotive brake disc rotor
    (Elsevier B. V., 2006-11-15) Ripley, MI; Kirstein, O
    Runout, and consequent juddering and pulsation through the brake pedal, is a multi-million dollar per year warranty problem for car manufacturers. There is some suspicion that the runout can be caused by relaxation of residual casting stresses when the disc is overheated during severe-braking episodes. We report here neutron-diffraction measurements of the levels and distribution of residual strains in a used cast iron brake disc rotor. The difficulties of measuring stresses in grey cast iron are outlined and three-dimensional residual-strain distributions are presented and their possible effects discussed. Crown Copyright © 2006 Published by Elsevier B.V
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    Residual stresses in Al7075 alloy laser cladded with Al-12Si alloy powder
    (The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2006-11-27) Durandet, Y; Bendeich, PJ; Ripley, MI; Liu, Q; Brandt, M
    Compared to conventional arc-welding processes commonly used to repair aluminium (Al) components, laser-cladding involves narrower heat affected zones (HAZ), lower overall heat input and less part distortion. With the development of high power lasers, it has become an attractive technology for the refurbishment of high value added structural airframe components in commercial and military aircrafts, especially those made of hard-to-weld age hardenable Al 7xxx series alloys. Laser cladding of 6.35mm thick rolled plates of Al7075 alloy was performed at IRIS using a high power Nd:YAG Laser and an Al-128i alloy powder as the filler repair material. Residual stress profiles through the clad plate thickness were measured using neutron diffraction scattering at ANSTO. Results showed the laser cladding pattern on residual stress profiles in directions longitudinal and transverse to the plate rolling direction. © The Authors
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    Residual stresses in cast iron automotive brake disc rotors
    (The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Ripley, MI; Kirstein, O
    Runout, and consequent juddering and pulsation through the brake pedal, is a multi-million dollar per year warranty problem for car manufacturers. There is some suspicion that the runout can be caused by relaxation of residual casting stresses when the disc is overheated during severe-braking episodes. We report here neutron-diffraction measurements of the levels and distribution of residual strains in a used cast iron brake disc rotor. The difficulties of measuring stresses in grey cast iron are outlined and three-dimensional residual-strain distributions are presented and their possible effects discussed. © The Authors