On melting thresholds of the film-substrate system under irradiation with a low-energy high-current electron beam

The effect of film material thermal conductivity on the melting threshold of the film-substrate system depending on the film thickness during a low-energy high-current electron beam (LEHCEB) irradiation was analyzed based on the numerical solution of the one-dimensional unsteady heat equation with a volumetric thermal source. Experimentally obtained oscillograms of the beam current at the collector and the accelerating voltage were used to simulate the heating source. Numerical variations of the film thermal conductivity were carried out within a wide range, overlapping the entire range for real materials. The dependence of the melting threshold of a homogeneous material on thermal conductivity was determined. The general regularities of the behavior of film and substrate melting thresholds depending on the film thickness were also established.