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Brittle Failure

The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

Zhi Li – 1st expert on this subject based on the ideXlab platform

  • an evaluation of the Failure modes transition and the christensen ductile Brittle Failure theory using molecular dynamics
    Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2018
    Co-Authors: Richard N Christensen, Zhi Li

    Abstract:

    The Christensen ductile/Brittle Failure theory can be interpreted in terms of the associated Failure modes, those of shear bands and voids nucleation. Their conjunction is then termed as the failur…

  • An evaluation of the Failure modes transition and the Christensen ductile/Brittle Failure theory using molecular dynamics
    Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2018
    Co-Authors: Richard N Christensen, Zhi Li

    Abstract:

    The Christensen ductile/Brittle Failure theory can be interpreted in terms of the associated Failure modes, those of shear bands and voids nucleation. Their conjunction is then termed as the failur…

Richard N Christensen – 2nd expert on this subject based on the ideXlab platform

  • an evaluation of the Failure modes transition and the christensen ductile Brittle Failure theory using molecular dynamics
    Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2018
    Co-Authors: Richard N Christensen, Zhi Li

    Abstract:

    The Christensen ductile/Brittle Failure theory can be interpreted in terms of the associated Failure modes, those of shear bands and voids nucleation. Their conjunction is then termed as the failur…

  • An evaluation of the Failure modes transition and the Christensen ductile/Brittle Failure theory using molecular dynamics
    Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2018
    Co-Authors: Richard N Christensen, Zhi Li

    Abstract:

    The Christensen ductile/Brittle Failure theory can be interpreted in terms of the associated Failure modes, those of shear bands and voids nucleation. Their conjunction is then termed as the failur…

William A Goddard – 3rd expert on this subject based on the ideXlab platform

  • atomistic explanation of Brittle Failure of thermoelectric skutterudite cosb3
    Acta Materialia, 2016
    Co-Authors: Guodong Li, Q An, William A Goddard, Riley Hanus, Pengcheng Zhai, Qingjie Zhang, Jeffrey G Snyder

    Abstract:

    CoSb_3 based skutterudite thermoelectric material has superior thermoelectric properties, but the low fracture toughness prevents its widespread commercial application. To determine the origin of its Brittle Failure, we examined the response of shear deformation in CoSb3 along the most plausible slip system (010)/ , using large-scale molecular dynamics simulations. We find that the Brittle Failure of CoSb_3 arises from the formation of shear bands due to the destruction of Sb4-rings and the slippage of Co-octahedraes. This leads to the breakage of Co-octahedraes and cavitation, resulting in the crack opening and mechanical Failure.

  • atomistic origin of Brittle Failure of boron carbide from large scale reactive dynamics simulations suggestions toward improved ductility
    Physical Review Letters, 2015
    Co-Authors: Q An, William A Goddard

    Abstract:

    Ceramics are strong, but their low fracture toughness prevents extended engineering applications. In particular, boron carbide (B_4C), the third hardest material in nature, has not been incorporated into many commercial applications because it exhibits anomalous Failure when subjected to hypervelocity impact. To determine the atomistic origin of this Brittle Failure, we performed large-scale (∼200 000  atoms/cell) reactive-molecular-dynamics simulations of shear deformations of B_4C, using the quantum-mechanics-derived reactive force field simulation. We examined the (0001)/⟨101¯0⟩ slip system related to deformation twinning and the (011¯1¯)/⟨1¯101⟩ slip system related to amorphous band formation. We find that Brittle Failure in B_4C arises from formation of higher density amorphous bands due to fracture of the icosahedra, a unique feature of these boron based materials. This leads to negative pressure and cavitation resulting in crack opening. Thus, to design ductile materials based on B_4C we propose alloying aimed at promoting shear relaxation through intericosahedral slip that avoids icosahedral fracture.

  • boron suboxide and boron subphosphide crystals hard ceramics that shear without Brittle Failure
    Chemistry of Materials, 2015
    Co-Authors: Q An, William A Goddard

    Abstract:

    Boron suboxide (B_6O), boron carbide (B_4C), and related materials are superhard. However, they exhibit low fracture toughness, which limits their engineering applications. Here we show the shear deformation mechanism of B_6O using density functional theory along the most plausible slip system (0111)/ . We discovered an unusual phenomenon in which the highly sheared system recovers its original crystal structure, which indicates the possibility of being sheared to a large strain without Failure. We also found a similar structural recovery in boron subphosphide (B_(12)P_2) for shearing along the same slip system. In contrast, for components of B_4C, we found Brittle Failure. These novel deformation mechanisms under high shear deformation conditions suggest that a key element to designing ductile hard materials is to couple the icosahedra via one- or two-atom chains that allow the system to shear by walking the intericosahedral bonds and chain bonds alternately to accommodate large shear without fracturing the icosahedra.