Surface strain-hardening of iron alloys with an intense pulsed electron beam

Results are presented from study of surface strain-hardening and measurements of the structure of carbon (St. 45, U7A, 40Kh) and alloy (R6M5, Kh6VF) steels subjected to surface fusion by pulsed electron beams with the following parameters: electron energy 20–250 keV, pulse duration 5·10^–8–3·10^–4 sec, power density 10⁵–10⁹ W/cm³. It is shown that the microhardness of the surface of most alloys increases by a factor of 1.2–1.7 on quenched specimens and by a factor of 2.5–3.5 on unquenched specimens, depending on the regime. Microhardness increases in the surface layer due to quenching from the liquid state. An increase in electron energy from 40 to 250 keV with a pulse duration of 6·-10^–8 sec leads to a severalfold increase in the thickness of the strengthened layers and to a shift of the microhardness peak from the surface to a depth of 70 m. Here, microhardness reaches 2000 kgf/mm². This is due to an increase in the mean free path of the electrons in the metal and displacement of the energy-release maximum of the bundle deeper into the specimen.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, No. 6, pp. 38–43, June, 1985.