UNIAXIAL TENSILE TEST AND WEAR IN METALS

The reorientation of atoms by frictional shear deformation at the surf ace of metals can induce cracks at the boundary of the grains. The cra cks grow and propagate in regions where the hydrostatic component of s tress in least compressive because the compressive component restores the cracks by three-dimensional crystallizing pi-bondings. Materials w ith Luder's bands have only a small amount of wear at the initial stat e, which suggests that initial frictional shear deformation is consume d in the formation of the Luder's bands. The average amounts of wear o f the materials increase very steeply as the value of phi(u), i.e. the stress-strain ratio at the ultimate point, decreases. (C) 1998 Elsevi er Science S.A. All rights reserved.