DevitrificationstudiesofZr–PdandZr–Pd–Cumetallicglasses M.J. Kramer a, * , M.F. Besser a , N. Yang a , E. Rozhkova a , D.J. Sordelet a , Y. Zhang b , P.L. Lee b a Metal and Ceramic Sciences Program, Ames Laboratory (USDOE), Department of Materials Science and Engineering, Iowa State University, 37 Wilhelm Hall, Ames, IA 50011-3020, USA b Advance Photon Source (APS), Argonne National Laboratory, Argonne, IL 60439, USA Abstract High temperature X-ray diffraction (HTXRD) is used to investigate the devitrification pathway for two related Zr- basedmetallicglasses,Zr 70 Pd 30 andZr 70 Pd 20 Cu 10 .Bothalloyshavesimilaras-quenchedstructuresandinitiallydevitrify to form a meta-stable quasicrystalline phase. The HTXRD data for the Zr 70 Pd 30 alloy shows the coexistence of the quasicrystalline and the Zr 2 Pd (I4/mmm) crystalline phases over a range of 25 K. Conversely, the Zr 70 Pd 20 Cu 10 alloy shows an additional transformation of the quasicrystalline phase to a meta-stable Zr 2 (PdCu) intermetallic (Zr 2 Si type structure, I4/mcm) that polymorphically transforms to the Zr 2 Ni type structure (I4/mmm) over a very narrow tem- perature range. Ó 2003 Elsevier Science B.V. All rights reserved. PACS: 81.05.Kf; 61.10.Nz; 64.70.Kb; 61.44.Br 1. Introduction Understanding solid state transformations and associated changes in crystal chemistry is a crucial endeavor in materials science and mineralogy. Various techniques are available to study trans- formation kinetics (e.g., thermal analysis, infrared spectroscopy,andmagneticmeasurementmethods tonameafew),yetonlydiffractionstudiesprovide the details of the lattice parameters and atomic positions necessary to fully characterize the struc- ture of the materials. In the past, studying the dynamics of crystal structure transformations us- ing X-ray and neutron diffraction was limited due to insufficient flux and the inadequate detectors. Advances in third generation synchrotron sources nowprovidesufficientphotonfluxathigherX-ray energies (>40 keV) to measure fully refinable X- ray diffraction pattern in less than a few seconds. Precise structural information can be obtained from the structural refinements [1]. The 2D de- tectors provide the capability to record data at a fast rate. It is now possible to obtain dynamic structuralinformationatheatingratesonparwith thermal analysis (e.g., 5–50 K/min) [2]. Within the large number of systems that form metallicglasses,severalZr-basedalloysareunique inthatoveralargerangeofcompositions,ameta- stable quasicrystalline phase forms as the primary devitrification product [3–8]. The formation of a * Corresponding author. Tel.: +1-515 294 0275; fax: +1-515 294 4291. E-mail address: mjkramer@ameslab.gov (M.J. Kramer). 0022-3093/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0022-3093(02)01984-1 Journal of Non-Crystalline Solids 317 (2003) 62–70 www.elsevier.com/locate/jnoncrysol