Evolution of residual stress states in surface layers of an AISI D2 steel treated by low energy high current pulsed electron beam

The quantitative evolution of the residual stress states in the surface layers of an AISI D2 steel after Low Energy High Current Pulsed Electron Beam (LEHCPEB) treatment has been investigated by using X-ray diffraction technique. The initial material contained mainly ferrite plus carbides and the ferrite had a compressive stress of about 560 MPa. After the LEHCPEB treatment, the residual stress of the ferrite in the surface layers became tensile in nature, reaching values as high as 730 MPa. A residual tensile stress also existed in the austenite formed at the surface. The stress increased from 170 MPa after 5 pulses to 700 MPa after 25 pulses of treatment. The evolution of the residual stress state in the surface layers can be explained by taking into account the fast thermal cycle, deformations induced by the dynamic thermal stress at the surface together with melting and phase transformations generated by the LEHCPEB treatment. (C) 2012 Elsevier Ltd. All rights reserved.