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★ ★ ★ 小木虫(金币+0.5):给个红包,谢谢回帖 imrsfb(金币+2, MM-EPI+1): 谢谢专家的详细解答! 2011-05-04 08:50:52
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Large dimple is called "dominant void", part of "microvoid Coalescence or Dimple Fracture" - usually occurs under single load or tearing. This is shown by depressions in the microstructure called dimples, which occur from microvoid emergence in places of high local plastic deformation. Under increased strain micrvoids grow, coalescence, until rupture occurs, thus dimple rupture. Dimple size and shape depends on the type of loading and extent of microvoid emergence. When a material is put under uniaxial tensile loading, equiaxed dimples appear which have complete rims. Under a tear loading the dimples are elongated, the rims of the dimples are not complete and the dimples are in the same direction as the loading. Shear loading has the same features as tear loading except the dimples are in opposite directions. The following sentences provide other common terminology associated with dimple fracture. Oval dimples occur when a large void intersects a smaller subsurface void, the dimples form an oval shape and exhibit complete rims. A serpentine glide is an interwoven pattern of glide plane decohesion steps. Ripples are partially smoothed out areas of serpentine glide. A stretched area is a flat, featureless area resulting from further straining of a ripple pattern. Intergranular dimple rupture occurs along grain boundaries due to nucleation and coalescence of voids at grain boundaries. |
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