High-Accuracy X-Ray Diffraction Analysis of Phase Evolution Sequence During Devitrification of Cu50Zr50 Metallic Glass

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2011-05, Vol.42 (5), p.1144-1153
• Main Authors: Kalay, I., Kramer, M. J., Napolitano, R. E.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Metallic Materials; Nanotechnology; Structural Materials; Surfaces and Interfaces; Thin Films
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-010-0531-9

Real-time high-energy X-ray diffraction (HEXRD) was used to investigate the crystallization kinetics and phase selection sequence for constant-heating-rate devitrification of fully amorphous Cu 50 Zr 50 , using heating rates from 10 K/min to 60 K/min (10 °C/min to 60 °C/min). In situ HEXRD patterns were obtained by the constant-rate heating of melt-spun ribbons under synchrotron radiation. High-accuracy phase identification and quantitative assessment of phase fraction evolution though the duration of the observed transformations were performed using a Rietveld refinement method. Results for 10 K/min (10 °C/min) heating show the apparent simultaneous formation of three phases, orthorhombic Cu 10 Zr 7 , tetragonal CuZr 2 (C11 b ), and cubic CuZr (B2), at 706 K (433 °C), followed immediately by the dissolution of the CuZr (B2) phase upon continued heating to 789 K (516 °C). Continued heating results in reprecipitation of the CuZr (B2) phase at 1002 K (729 °C), with the material transforming completely to CuZr (B2) by 1045 K (772 °C). The Cu 5 Zr 8 phase, previously reported to be a devitrification product in C 50 Zr 50 , was not observed in the present study.