Surface Modification of Cobalt Chrome Molybdenum Cast Alloy by Electron Beam Irradiation

摘要

We irradiated the surface of a Co-Cr-Mo cast alloy plate with an electron beam in order to increase the surface hardness. An accelerating voltage of 40 kV and a current of 1～10 mA of the irradiated electron beam were used. The irradiation time for a single dot was 0.1 ms and the distance between dots (dot pitch) was 0.2 mm, corresponding to a scanning speed of 200 mm/s. A fine cellular structure was obtained by irradiating a low current electron beam. When a high current electron beam (more than 8 mA) was used for the irradiation, fine granular carbides were synthesized. The Vickers hardness of the base metal of 410 HV was increased to about 480～530 HV by the electron beam irradiation.