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 ::That paper refers to the Bauschinger effect (the phenomenon wherein plastic deformation of a metal raises its tensile yield strength but decreases its compressive yield strength) and hysteresis in metals. I do not see how this relates directly to the question at hand. The degree of deformation in the razor's blade through shaving is negligible, I would have thought, and in any case unidirectional. Where is the reverse load?  Where, in that paper, is the reference to the metal slowly changing shape in the 50 hr period?  Why would we care to allow the blade to regain elasticity, assuming its edge is being ""overstressed"" by shaving? Inelasticity is exactly what we need, not a floppy edge.  "