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Title: Gradient changes in structural condition of the B2 phase of NiTi surface layers after electron-beam treatments

Structural conditions of the B2 phase of the Ti{sub 49.5}Ni{sub 50.5} alloy surface layers before and after electron-beam treatments (pulse duration τ = 150 μs, number of pulses n = 5, beam energy density E ≤ 20 J/cm{sup 2}) were studied by X-ray diffraction analysis. Analysis of the X-ray patterns demonstrates that surface layers modified by electron beam treatment contain phase with B2{sup surf} structure. It is revealed that the lattice parameter of the B2{sup surf} phase in the surface (modified) layer is also higher than the lattice parameter of the B2 phase in the underlying layer (a{sub B2} = 3.0159±0.0005). The values of lattice parameter of phase B2{sup surf} amounted a{sub B2}{sup surf} = 3.0316±0.0005 Å and a{sub B2}{sup surf} = 3.0252±0.0005 Å, for the specimens after electron-beam treatment at E{sub 1} = 15 J/cm{sup 2} and E{sub 2} = 20 J/cm{sup 2}, respectively. Inflated lattice parameters a{sub B2}{sup surf} are associated with changes in the chemical composition and the presence of residual stresses in the surface region of the samples after electron-beam treatments.
Authors:
;  [1] ;  [2] ;  [3]
  1. Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk State University, Tomsk, 634050 (Russian Federation)
  2. Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)
  3. Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)
Publication Date:
OSTI Identifier:
22390427
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1623; Journal Issue: 1; Conference: International Conference on Physical Mesomechanics of Multilevel Systems 2014, Tomsk (Russian Federation), 3-5 Sep 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHEMICAL COMPOSITION; CRYSTAL LATTICES; ELECTRON BEAMS; ENERGY DENSITY; IRRADIATION; LATTICE PARAMETERS; LAYERS; NICKEL ALLOYS; RESIDUAL STRESSES; SURFACES; TITANIUM ALLOYS; X-RAY DIFFRACTION