X-Ray Diffraction Study of Atomic Short-Range Order in Pt–15.0 at.% Cr Alloy

Abstract

The X-ray diffuse scattering intensities were measured at room temperature for the Pt rich Pt–15.0 at.% Cr single crystal quenched from 800°C three-dimensionally. The atomic short-range order (ASRO) intensity component from the total diffuse ones was separated with the use of Borie–Sparks method [Acta Cryst. A 27 (1971) 198]. The ASRO intensity maxima were observed at the 100, 110 and their equivalent positions (X-point) on the reciprocal lattice plane, which are widely diffused. We did not find any ASRO diffuse scattering intensity at \(\frac{1}{2}\frac{1}{2}\frac{1}{2}\) and its equivalent positions (L-point) for the alloy. The diffuse maxima at the X-point are due to the Cu 3 Au type ASRO in the present alloy case. The ASRO parameters were determined from the data and the required number of ASRO parameters, to reconstruct the peaks, indicates that the maxima are widely diffused. The correlation length is deduced to be about 10 A. Any superlattice reflections were not found from the specimen, which was ...