J. Phys. IV France
Volume 112, October 2003
Page(s) 693 - 696

J. Phys. IV France
112 (2003) 693
DOI: 10.1051/jp4:2003977

Structure studies of the R-phase using the X-ray and electron diffraction method

T. Goryczka and H. Morawiec

University of Silesia, Institute of Physics and Chemistry of Metals, Bankowa 12, 40-006 Katowice, Poland

The R-phase was induced in polycrystalline 50.6at% Ni-Ti and 51.2at% Ni-Ti alloys by deformation of $\varepsilon=5\%$ and annealing at 350°C for 70 hours. This procedure allowed for a good separation of transformations: $\rm B2{\to}R$ and $\rm R{\to}B19'$. The X-ray diffraction patterns were refined with Rietveld method for three structure models of the following space groups: P3, P-3 and  P31m. The atomic positions were calculated from the Patterson maps determined from the LeBail method. The comparable lowest value of reliability factors was obtained from the Rietveld refinement for P3 and P-3 space groups. Electron diffraction patterns registered for basics zones were compared with kinematically calculated models. Profile line analysis was done in rows with significant differences. All results supported the P-3 model.

© EDP Sciences 2003