Structural phase changes in a titanium-silicon system modified by high-current electron beams and compression plasma flows

Abstract

Structural phase changes in a titanium-silicon system treated by low-energy high-current electron beams (HCEBs) and compression plasma flows (CPFs) with the duration 100 μs and the energy density 12–15 J/cm2 are studied. Scanning electron microscopy, X-ray diffraction and electron microprobe analysis are used in this work. The formation of a titanium-doped silicon layer 10–25 μm thick, titanium silicides (TiSi2 under HCEBs and Ti5Si3 under CPF treatment), silicon dendrites, and needle-like eutectics (typical size of precipitates is about 50 nm) is revealed. It is shown via the results of numerical simulation that the thickness of the metal-doped layer is mainly controlled by the power density value and the surface nonuniformity of the heat flow over the target surface. The thermodynamic regularities of phase formation are discussed, taking into account heat transfer between the silicide nuclei and solid silicon.