Temperature profile and crater formation induced in high-current pulsed electron beam processing

We study in this article the formation mechanism of craters on a metal surface during the high current pulsed electron beam processing. Based on experimental investigations and a physical model, the melting process and their temperature profiles are simulated for substrates of aluminum and steels. Initial melting positions, crater depths, and melting layer thickness are computed, the results being in a good agreement with experimental data. It is also confirmed that the temperature rises faster at a subsurface layer instead of at the outermost surface due to the maximum energy deposition located at about 1/3 of the total penetration depth of the beam. Such a subsurface layer heating and melting mechanism causes eruptions of the subsurface layer liquid matters through the outermost surface and produces the typical surface crater morphology