Modification of material surfaces by the pulsed electron beam facility “GESA”

Pulsed heat treatment is a modem and ecologically sound technique of surface modification. The special feature of pulsed heat treatment is the possibility of applying high heating and cooling rates is. Fast cooling rates (as much as 10⁷ K/s) of the heated layer cause a change in its physical properties; metastable phases with amorphous and nanocrystalline structures are formed. For investigation of the modifications of material properties by pulsed electron beams a new powerful electron beam facility GESA was developed and manufactured [1]. It produces an electron beam with a kinetic energy of 50 – 150 keV, a max. beam current of 500 A, a beam diameter of 6 – 10 cm and a pulse duration of 5 – 40 µs. All marked beam parameters (energy, current density, pulse duration) are controlled. The paper presents the results of investigation focused on the transformation of the micro-structure, alloy formation and high temperature corrosion behavior of the Superalloy MCrAlY treated by an electron beam. Further the improvement of tribological properties by pulsed heat treatment of tappets used in car engines, consisting of a 16MnCr5 steel, are described.