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6860 |
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Tuesday, March 09, 2021, Hall 1 4:05 PM Surface Treatment |
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Influence of the electron beam parameters on the structure and properties of electron beam surface treated Ti6Al4V alloy |
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Peter Petrov* / Institute of Electronics, Bulgarian Academy of Sciecnes, Bulgaria Maria Ormanova / Institute of Electronics, Bulgarian Academy of Sciences, Bulgaria Stefan Valkov/ Institute of Electronics, Bulgarian Academy of Sciences, Bulgaria |
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The titanium and its alloys are widely used in the field of the modern medicine, for manufacturing of implants, aerospace and automotive industries, etc. due to their excellent resistance to corrosion, high stiffness and toughness and remarkable strength-to-weight ratio. However, some drawbacks due to the low hardness and poor wear resistance can be mentioned and the applications of these materials are still limited. The discussed limitations depend mostly on the surface properties of the materials, and they can be overcome by an appropriate surface modification. Currently, the electron beam treatment techniques are among the most promising methods for surface modification. In this work Ti6Al4V alloy was electron beam surface treated by continuous electron beam. Electron beam treatment is carried out on the evobeam Cube 3 kW/60kV welding unit (Evo Beam, Germany). During the treatment process the accelerating voltage (U) was 60 kV, the beam current was from 10 to 40 mA, the electron beam scanning frequency was from 1 kHz to 20 kHz. The beam diameter was 0.2 mm. The obtained phase composition was studied by X-ray diffraction. The experiments were performed in symmetrical B-B (Bragg-Brentano) mode using Cu K? (1.54Å) characteristic radiation. The patterns were registered in the range from 20° to 80° at 2? scale, with a step of 0.02° and counting time 3 s per step. The microstructure was studied by scanning electron microscope equipped with EDX microanalyzer. The EDX detector integrates a true standardless analysis with P/B ZAF quantitative corrections (Z being the atomic number correction factor; A–X-ray absorption correction factor; F–fluorescence correction factor. The hardness of the deposited films was studied by means of a nanomechanical tester. The experiment consisted of a total of 48 indentations (4 lines with 12 indentations each) with spacing of 80 µm and applied load of 50 mN. The experiments for the characterization of the surface topology were performed by means of Atomic Force Microscopy (AFM). The measurements were carried out via non-contact mode, where the curvature radius of the silicon nitride tip was 10nm. The force constant was 43N/m. The obtained surface properties of the electron beam treated Ti6Al4V alloy are discussed concerning the applied technological conditions, and formed phase composition and microstructure. |