Change of the Modulus of Elasticity of the Surface Nonasrtuctured Layer on U8 Steel

The change of the modulus of elasticity of surface nanocrystalline structure, formed by mechanical-pulse treatment on U8 steel was studied by the Oliver–Pharr indentation method. The increment of elastic modulus by 17% compared with matrix structure is shown. This is explained by the change of electron configuration of iron, namely by increase in the contribution of d-orbitals into metallic bond due to the influence of high pressure under treatment, thus confirming the theory about higher interaction between atoms inside the metal and its weakening on the surface. The inverse relationship between modules of elasticity and friction coefficients for different metals is shown.