Temperature–stress fields and related phenomena induced by a high current pulsed electron beam

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Physical models and numerical simulations are applied to describe the thermal–dynamical processes of the high current pulsed electron beam (HCPEB) treatment. The simulation of the temperature distributions reveals an ultrahigh heating/cooling rate in the order of 10 8–10 9 K/s, as well as rapid melting and re-solidification within microseconds in time and micrometers in depth. It is also pointed out that the melting starts at a sublayer about 1–2 μm in depth, which constitutes the crater formation mechanism. A temperature-induced dynamic thermal stress fields can then generate three principal stress, the quasi-static stress, the thermoelastic stress and the shock stress, the latter two being stress waves. The thermoelastic stress wave has small amplitudes less than 0.1 MPa. The shock stress wave however is a typical nonlinear wave, several hundreds of MPa in amplitudes, much stronger than the thermoelastic stress wave, and has a strong impact on materials structure and properties far beyond the heat-affected zone. The maximum compressive quasi-static stress in the surface layer reaches several hundreds of MPa, which easily induces surface deformation in metallic materials.