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  1. Article

    Open Access

    Evaluation of Fracture Toughness Measurements Using Chevron-Notched Silicon and Tungsten Microcantilevers

    Measuring the fracture behavior of small specimens of semibrittle materials such as tungsten is often difficult due to the lack of crack stability and a high ratio of the crack tip plastic zone size to specime...

    B.-S. Li, T. J. Marrow, S. G. Roberts, D. E. J. Armstrong in JOM (2019)

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  2. Article

    Erratum to: Measuring fracture toughness of coatings using focused-ion-beam-machined microbeams

    In Di Maio and Roberts1, Equation (3) had an incorrect term listed in the bracketed portion of the equation. The correct equation is as follows:

    D. Di Maio, S. G. Roberts in Journal of Materials Research (2017)

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  3. No Access

    Chapter and Conference Paper

    Simulation of Tsunami and Flash Floods

    Impacts to the built environment from hazards such tsunami or flash floods are critical in understanding the economic and social effects on our communities. In order to simulate the behaviour of water flow fro...

    S. G. Roberts, O. M. Nielsen, J. Jakeman in Modeling, Simulation and Optimization of C… (2008)

  4. No Access

    Article

    Mechanical properties and microstructure of Al2O3/mullite composite

    An Al2O3/5 vol.% mullite composite was synthesized by using reaction sintering of Al2O3/0.78 wt.% SiC at 1,600 °C for 2 h in air. The phase analysis of the Al2O3/mullite composite was carried out using X-ray diff...

    F. C. Zhang, H. H. Luo, S. G. Roberts in Journal of Materials Science (2007)

  5. No Access

    Article

    Low-temperature fracture mechanisms in a spheroidised reactor pressure vessel steel

    The micromechanisms of fracture of a spheroidised A533B reactor pressure vessel steel over the temperature range of −190°C to + 60°C were investigated by performing uniaxial tensile tests on double-notched cyl...

    A. Kumar, S. G. Roberts, A. J. Wilkinson in International Journal of Fracture (2007)

  6. No Access

    Chapter and Conference Paper

    Relating Cleavage Crack Nucleation to Cracked Carbides in A533B Steel

    At low temperatures, ferritic steels exhibit a change in fracture behaviour, from ductile fracture with high fracture energies accompanied by a high degree of plasticity, to brittle cleavage fracture whereby f...

    A. Kumar, S. G. Roberts in Fracture of Nano and Engineering Materials and Structures (2006)

  7. No Access

    Article

    Measuring fracture toughness of coatings using focused-ion-beam-machined microbeams

    Measuring the toughness of brittle coatings has always been a difficult task. Coatings are often too thin to easily prepare a freestanding sample of a defined geometry to use standard toughness measuring techn...

    D. Di Maio, S. G. Roberts in Journal of Materials Research (2005)

  8. No Access

    Article

    Wet erosion behaviour of low SiC alumina-SiC nanocomposites

    We have investigated the erosive wear behaviour of alumina and Al2O3-SiC “nanocomposites” with SiC content between 1 and 5%. Nanocomposites (grain sizes between 3.15 and 7.16 μm) and alumina (grain size 4.43 μm) ...

    H. Kara, S. G. Roberts in Journal of Materials Science (2002)

  9. No Access

    Article

    Nanoindentation investigation of micro-fracture wear mechanisms in polycrystalline alumina

    The initiation of surface damage under point loading has been investigated in polycrystalline alumina materials using low load continuous depth-sensing indentation equipment (nanoindentation). Pure alumina and...

    P. C. Twigg, F. L. Riley, S. G. Roberts in Journal of Materials Science (2002)

  10. No Access

    Chapter

    Modelling Brittle-Ductile Transitions

    This paper outlines current approaches to modelling fracture and the brittle-ductile transition both in simple materials and in microstructurally complex materials such as steel. The models cover a very wide r...

    S. G. Roberts in Multiscale Phenomena in Plasticity: From E… (2000)

  11. No Access

    Article

    A Multiple Slip Plane Model for Crack-Tip Plasticity

    A single slip plane dislocation dynamics based model for the brittle to ductile transition has been extended to have multiple slip planes around the crack-tip. The crack-tip plastic behaviour is studied for a ...

    S. J. Noronha, S. G. Roberts, A. J. Wilkinson in MRS Online Proceedings Library (1999)

  12. No Access

    Article

    Residual Stress Determination and Subsurface Microstructure in Ground and Polished Alumina/Silicon Carbide Nanocomposites and Monolithic Alumina Ceramics

    The surface residual stress state induced by grinding and polishing an alumina/silicon carbide nanocomposite and monolithic alumina has been investigated using Hertzian indentation and fluorescence spectroscop...

    H. Z. Wu, S. G. Roberts, A. J. Winn, B. Derby in MRS Online Proceedings Library (1999)

  13. No Access

    Article

    Crack Healing in an Alumina/Silicon Carbide Nanocomposite After Grinding and Annealing

    Alumina/silicon carbide nanocomposites are known to show their highest strength levels after surface grinding followed by annealing. After annealing in flowing argon, nanocomposites with very coarsely ground s...

    H. Z. Wu, J. M. Titchmarsh, S. G. Roberts, B. Derby in MRS Online Proceedings Library (1999)

  14. No Access

    Article

    Grain boundary influence on the mechanical behaviour of oriented bicrystals

    It is shown through several experiments centred on dislocation transmission through a GB that relating macroscopic mechanical properties of a bicrystalline specimen to the atomic structure of the GB or to loca...

    A. Jacques, A. George, S. G. Roberts, M. Polcarova, J. Bradler… in Interface Science (1997)

  15. No Access

    Article

    Surface flaw distributions in brittle materials and Hertzian fracture

    Refined mode I and mode II stress intensity factors for short cracks perpendicular to a free surface driven by a Hertzian indenter have been calculated for the case where the sphere and substrate are made of t...

    P. D. Warren, D. A. Hills, S. G. Roberts in Journal of Materials Research (1994)

  16. No Access

    Article

    Nanomechanical Response of Materials and Thin Film Systems: Finite Element Simulation

    Finite element simulation of the nanoindentation process has been carried out to investigate the nanomechanical response of materials and thin film systems. The influence of the geometry of the indenter, frict...

    S. A. Syed Asif, B. Derby, S. G. Roberts in MRS Online Proceedings Library (1994)

  17. No Access

    Chapter

    Indentation Creep in Semi-Brittle Materials

    For brittle solids microhardness testing may be the only means of producing plastic flow over a wide temperature range. Indentation creep is a possible method for assessing the time-dependent deformation of br...

    N. M. Everitt, S. G. Roberts in Constitutive Laws of Plastic Deformation and Fracture (1990)

  18. No Access

    Chapter

    The Brittle-To-Ductile Transition in Silicon

    Recent experiments on the brittle-ductile transition (BDT) of precracked specimens of Si show that the transition is sharp, and that the strain rate dependence of the transition temperature, Tc, is controlled by ...

    P. B. Hirsch, S. G. Roberts, J. Samuels… in Mechanics of Creep Brittle Materials 1 (1989)

  19. No Access

    Article

    Slip Patterns and Slip Modes Under Knoop Indentations on (001) GaAs

    Slip patterns around <110> Knoop indentations on <001> GaAs were investigated by cross-sectioning, etching and TEM. The roles of As(g) and Ga(g) perfect and partial dislocations in different parts of the “plas...

    C.-D. Qin, S. G. Roberts in MRS Online Proceedings Library (1988)

  20. No Access

    Article

    Microhardness response of nitrogen-implanted and X-irradiated lithium fluoride

    The microhardness behaviour of {001} faces of LiF has been investigated before and after both nitrogen-ion implantation and implantation followed by X-irradiation. Implantation alone produced no changes in eit...

    S. G. Roberts, T. F. Page in Journal of Materials Science (1986)

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