MICROSTRUCTURE AND PROPERTY MODIFICATIONS IN MOULD STEELS TREATED BY PULSED ELECTRON BEAMS

摘要

Surface modifications on AISI H13 and D2 mould steels generated by the low energy high current pulsed electron beam (LEHCPEB) treatments have been investigated. From the observations of SEM, XRD and electron back scattering diffraction (EBSD) determinations, the microstructure modifications were studied in details. It is found that the formation of the metastable micorstructures in the surface layer are related to the very rapid heating, melting, solidification and cooling induced by the LEHCPEB irradiation. After the LEHCPEB treatment, the wear resistance of the mould steels can be effectively improved. This can be mainly attributed to the higher hardness of the ultra fine structures formed on the top surface and the hardened subsurface layers after treatment.