Surface amorphization and mechanical enhancement of a Co-based hardfacing alloy by high-current pulsed electron beam treatment

Abstract

High-current pulsed electron beam treatment was applied to the Stellite 12 hardfacing alloy to investigate its effect on surficial modifications and the degree of consequent mechanical enhancement. The electron beam treatment produced a carbide-free modified layer comprising an outmost amorphous zone and an underlying nanocrystalline alpha-Co region. This duplex structure is considered to result from rapid melting and solidification with dissolution of pre-existing carbides. The beam-treated alloy exhibited markedly improved mechanical properties, with more than twofold higher surface hardness and wear rate reduced by over 60% as compared to the initial state. These findings demonstrate that the suggested surface treatment utilizing a pulsed electron beam is an effective engineering method for reinforcing the Co-based hardfacing alloy without compositional tuning or composite-type structuring.