Combined electron-ion-plasma doping of a titanium surface with yttrium: Analyzing structure and properties

Formation Mechanism of Micro- and Nanocrystalline Surface Layers in Titanium and Aluminum Alloys in Electron Beam Irradiation

“…The data on a molten layer thickness, when the thermal electric convection is a key mechanism responsible for the formation of cell structures, have demonstrated this effect is relevant for h~10-100 µm. As reported in studies [7,8,15,16], the thickness of molten layers ranges from~10 to 80 µm in electron beam irradiation. This fact suggests thermoelectric effects represent one of the basic formation mechanisms of micro-and nanodimensional structure elements in electron beam processing.…”

“…The thermoelectric effect shifts the maximal growth rate to the wavelength λ m = 76 µm, and the critical wavelength is λ m = 18 µm in these conditions ( Figure 4 curve 3 and 4). From the experimental data it can be seen [7,8] that cell structures develop due to the electron beam irradiation varying in a range from 100 to 600 nm, depending on processing conditions. The low frequency approximation (10) has shown this range of wavelengths is possible for electric field strength E 0~1 0 6 -10 7 V/m ( Figure 5 curve 1 and 2).…”

“…To form these layers concentrated energy flows are applied i.e., the heterogeneous plasma flow processing in conjunction with the succeeding low energy high current electron beam irradiation [4][5][6]. The latest research in this field [7,8] has highlighted microand nanocrystalline layers with a columnar structure ( Figure 1) form when irradiating titanium and silumin processed prior by the electric explosion plasma of yttrium powder. A thickness of a columnar crystallization layer is within a range from 1 to 1.5 µm (Figure 1a) in the Ti-Y system.…”