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Microstructure and mechanical properties of IF steel deformed during plane stress local torsion

Journal Article


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Abstract


  • Mechanical joints are inherently vulnerable to failure

    because the presence of the joint hole causes a stress

    concentration in the vicinity of the hole. The need for

    improvement of material strength around a fastener hole

    can be satisfied by severe plastic deformation (SPD) to

    produce ultrafine grains. The ultrafine grained (UFG)

    alloys produced by SPD processing possess higher

    strengths than their coarse-grained counterparts as a result

    of the reduced grain size. However, in some circumstances

    such as SPD processing of Al–Zn and Al–Mg alloys the

    decomposition of supersaturated solid solutions competes

    with the Hall–Petch effect and leads to a more pronounced

    softening of the material [1]. Another drawback of SPD

    processes is that they involve bulk deformation and large

    energy consumption [2]. It is therefore desirable to enhance

    the global behaviour of the material by limiting improvement

    of the material property by SPD to the location at

    which it is needed. Localized severe plastic deformation

    (LSPD) techniques, such as forward spiral extrusion [3]

    and friction stir processing [4], involve lower energy consumption.

    They modify the properties of materials locally

    and create a gradient of grain refinement, resulting in significant

    improvement in the mechanical properties of the

    processed samples. However, these techniques cannot be

    used for strengthening the material around fastener holes,

    and thus a method for improving the strength of material

    around the hole is needed.

    To reinforce the mechanical properties of material

    around a hole, the plane stress local torsion (PSLT) process,

    which involves a plane stress axi-symmetric torsional

    loading, is introduced. The PSLT takes advantage of large

    shearing strains induced around the intended hole position,

    through torsional deformation [5]. As a result, the material

    flows plastically within a thin annular zone around the

    fastener hole (AZFH). Because of the limited penetration

    of the flow localization zone into the material, a major

    proportion of deformation energy is consumed within the

    AZFH. The PSLT therefore consumes much less energy

    than do bulk grain refinement techniques.

UOW Authors


  •   Dehghan-Manshadi, A (external author)
  •   Thomson, P F. (external author)
  •   Shamdani, A H. (external author)
  •   Khoddam, S (external author)

Publication Date


  • 2012

Citation


  • Shamdani, A. H., Khoddam, S., Thomson, P. F. & Dehghan-Manshadi, A. (2012). Microstructure and mechanical properties of IF steel deformed during plane stress local torsion. Journal of Materials Science, 47 (3), 1582-1587.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8250&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/5318

Number Of Pages


  • 5

Start Page


  • 1582

End Page


  • 1587

Volume


  • 47

Issue


  • 3

Abstract


  • Mechanical joints are inherently vulnerable to failure

    because the presence of the joint hole causes a stress

    concentration in the vicinity of the hole. The need for

    improvement of material strength around a fastener hole

    can be satisfied by severe plastic deformation (SPD) to

    produce ultrafine grains. The ultrafine grained (UFG)

    alloys produced by SPD processing possess higher

    strengths than their coarse-grained counterparts as a result

    of the reduced grain size. However, in some circumstances

    such as SPD processing of Al–Zn and Al–Mg alloys the

    decomposition of supersaturated solid solutions competes

    with the Hall–Petch effect and leads to a more pronounced

    softening of the material [1]. Another drawback of SPD

    processes is that they involve bulk deformation and large

    energy consumption [2]. It is therefore desirable to enhance

    the global behaviour of the material by limiting improvement

    of the material property by SPD to the location at

    which it is needed. Localized severe plastic deformation

    (LSPD) techniques, such as forward spiral extrusion [3]

    and friction stir processing [4], involve lower energy consumption.

    They modify the properties of materials locally

    and create a gradient of grain refinement, resulting in significant

    improvement in the mechanical properties of the

    processed samples. However, these techniques cannot be

    used for strengthening the material around fastener holes,

    and thus a method for improving the strength of material

    around the hole is needed.

    To reinforce the mechanical properties of material

    around a hole, the plane stress local torsion (PSLT) process,

    which involves a plane stress axi-symmetric torsional

    loading, is introduced. The PSLT takes advantage of large

    shearing strains induced around the intended hole position,

    through torsional deformation [5]. As a result, the material

    flows plastically within a thin annular zone around the

    fastener hole (AZFH). Because of the limited penetration

    of the flow localization zone into the material, a major

    proportion of deformation energy is consumed within the

    AZFH. The PSLT therefore consumes much less energy

    than do bulk grain refinement techniques.

UOW Authors


  •   Dehghan-Manshadi, A (external author)
  •   Thomson, P F. (external author)
  •   Shamdani, A H. (external author)
  •   Khoddam, S (external author)

Publication Date


  • 2012

Citation


  • Shamdani, A. H., Khoddam, S., Thomson, P. F. & Dehghan-Manshadi, A. (2012). Microstructure and mechanical properties of IF steel deformed during plane stress local torsion. Journal of Materials Science, 47 (3), 1582-1587.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8250&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/5318

Number Of Pages


  • 5

Start Page


  • 1582

End Page


  • 1587

Volume


  • 47

Issue


  • 3