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

TitleHigh-Accuracy X-Ray Diffraction Analysis of Phase Evolution Sequence During Devitrification of Cu50Zr50 Metallic Glass
Publication TypeJournal Article
Year of Publication2011
AuthorsKalay I, Kramer MJ, Napolitano RE
Journal TitleMetallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
Volume42A
Pages1144-1153
Date Published05
ISBN Number1073-5623
Accession NumberISI:000288814700002
Keywordsalloys, copper-zirconium, crystal-structure, CRYSTALLIZATION, cu-zr system, high-strength, intermediate phases, mechanical-properties, stability, supercooled liquid
Abstract

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 Cu50Zr50, using heating rates from 10 K/min to 60 K/min (10 A degrees C/min to 60 A degrees 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 A degrees C/min) heating show the apparent simultaneous formation of three phases, orthorhombic Cu10Zr7, tetragonal CuZr2 (C11(b)), and cubic CuZr (B2), at 706 K (433 A degrees C), followed immediately by the dissolution of the CuZr (B2) phase upon continued heating to 789 K (516 A degrees C). Continued heating results in reprecipitation of the CuZr (B2) phase at 1002 K (729 A degrees C), with the material transforming completely to CuZr (B2) by 1045 K (772 A degrees C). The Cu5Zr8 phase, previously reported to be a devitrification product in C50Zr50, was not observed in the present study.

URL<Go to ISI>://000288814700002
DOI10.1007/s11661-010-0531-9
Alternate JournalMetall Mater Trans AMetall Mater Trans A