Microvoid coalescence

Microvoid coalescence
MVC fracture surface morphologies for a) tension, b) shear, and c) bending failures

Microvoid coalescence (MVC) is a high energy microscopic fracture mechanism observed in the majority of metallic alloys and in some engineering plastics.

Fracture process

MVC proceeds in three stages: nucleation, growth, and coalescence of microvoids. The nucleation of microvoids can be caused by particle cracking or interfacial failure between precipitate particles and the matrix. Microvoids grow during plastic flow of the matrix, and microvoids coalesce when adjacent microvoids link together or the material between microvoids experiences necking. Microvoid coalescence leads to fracture.[1]

Fracture surface morphologies

MVC can result in three distinct fracture morphologies based on the type of loading at failure. Tensile loading results in equiaxed dimples, which are spherical depressions a few micrometres in diameter that coalesce normal to the loading axis. Shear stresses will result elongated dimples, which are parabolic depressions that coalesce in planes of maximum shear stress. The depressions point back to the crack origin, and shear influenced failure will produce depressions that point in opposite directions on opposing fracture surfaces. Combined tension and bending will also produce the elongated dimple morphology, but the directions of the depressions will be in the same direction on both fracture surfaces.

References

  1. ^ Hertzberg, Richard W. Deformation and Fracture Mechanics of Engineering Materials, Fourth Edition. John Wiley and Sons, Inc, Hoboken, NJ: 1996.

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • microvoid coalescence — occurs due to the nucleation of microvoids, followed by their growth and eventual coalescence; initiation is caused by particle cracking or interfacial failure between an inclusion or precipitate particle and the surrounding matrix …   Mechanics glossary

  • coalescence — microvoid coalescence …   Mechanics glossary

  • Fracture — For other uses, see Fracture (disambiguation). v · d · e Materials failure modes …   Wikipedia

  • Intergranular fracture — An intergranular fracture is a fracture that follows the grains of the material. If the material has multiple lattice organizations, when one lattice ends and another begins, the fracture changes direction to follow the new grain. This results in …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”