Transmission electron microscopy studying of structural features of NiTi B2 phase formed under pulsed electron-beam impact

• Main Authors: Meisner, Ludmila L., Semin, Viktor O., Gudimova, Ekaterina Y., National Research Tomsk State University, Tomsk, 634050, Neiman, Alexey A., Lotkov, Alexander I., Ostapenko, Marina G., Koval, Nikolai N., Teresov, Anton D., Institute of High Current Electronics SB RAS, Tomsk, 634055
• Format: Conference Proceeding
• Language: English
• Subjects: BCC LATTICES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONCENTRATION RATIO; DEPTH; Diffraction patterns; Distortion; ELECTRON BEAMS; ELECTRON DIFFRACTION; ENERGY DENSITY; Flux density; Intermetallic compounds; Intermetallic phases; LAYERS; MATERIALS SCIENCE; MELTING; Microstructure; NICKEL ALLOYS; Nickel titanides; PARTICLES; Pulse duration; PULSES; SURFACES; THICKNESS; Titanium; TITANIUM ALLOYS; TRANSMISSION ELECTRON MICROSCOPY; Unit cell; X RADIATION; X ray analysis
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.4932837

By transmission electron microscopy method the evolution of structural-phase states on a depth of close to equiatomic NiTi modified layer has been studied. Modification performed by pulse impact on its surface low-energy high-current electron beam (beam energy density 10 J/sm2, 10 pulses, pulse duration 50mks). It is established that during the treatment in the layer thickness of 8–10 μm, the melting of primary B2 phase and contained therein as Ti2Ni phase particles occurs. The result is change in the concentration ratio of titanium and nickel in the direction of increasing titanium content, which was confirmed by X-ray analysis in the form of increased unit cell parameter B2 phase. Analysis of the electron diffraction pattern showed that the modified layer is characterized as a highly distorted structure on the basis of bcc lattice. Lattice distortions are maximal near the surface and extends to a depth of melt. In subjacent layer there is gradual decline lattice distortions is observed.