Structural Aspects of Zr+ Ion-Beam Surface Modification and Mechanical Properties of 12CrMoV Steel

Abstract

Surface modification is an effective way both to protect structural materials and to improve their mechanical properties. However under mechanical loading the distinction of elastic moduli of a modified surface layer and adjacent bulk material causes the stress concentrators to occur, whose relaxation may give rise to localized development of plastic deformation or fracture [1]. Under cyclic loading such distinction of the properties brings to multiple microcracking of strengthened surface layer, to act as structural micronotches [2, 3]. Therefore, optimized modes and parameters for surface layer modification are to be determined being a certain compromise between strength/ductility of the layer and its thickness etc.