Microscopic Observations of the Wear Sheet Formation by Delamination

S. Jahanmir, N. P. Suh, and E. P. Abrahamson, II, “Microscopic Observations of the Wear Sheet Formation by Delamination,” Wear, 28 (1974) 235-249.

A series of experimental results showing the process of wear sheet formation has been obtained by observing the wear tracks and the deformed subsurface of ductile metals using a scanning electron microscope. These results substantiate the delamination theory of wear. The experimentally observed delamination process initiates when the extensive sub-surface plastic deformation causes the nucleation of voids. With further deformation these voids elongate and link up to form long cracks in a direction nearly parallel to the wear surface. At a “critical” length, these cracks shear to the surface, yielding a wear particle in the form of a long thin sheet. The top surface of the wear sheet is generally smooth, while the fractured surface is rough, often showing dimples and ruptured needle points of typical ductile fracture. When the delamination process is slow, the wear track has a very cratered appearance. The process of delamination and the morphology of the wear surface and sheets are markedly influenced by the structure and microstructure of the material.

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