In situ observation of thermal expansion of tetragonal C11b phase in Zr₂Cu_(1-x)Od_x alloys

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Intermetallics

DOI:https://doi.org/10.1016/j.intermet.2009.05.016· OSTI ID:970477

Xu, Min ^[1]; Ye, Y. Y. ^[2]; Morris, James R ^[3]; Sordelet, D. J. ^[1]; Kramer, M. J. ^[4]

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1. Ames Laboratory and Iowa State University
2. Wuhan University
3. ORNL
4. Iowa State University

The C11b phase crystalline structure (structure type MoSi{sub 2}, space group I4/mmm) in the Zr{sub 2}Cu{sub (1-x)}Pd{sub x} (x = 0, 0.25, 0.5, 0.75 and 1) alloys was examined in situ using high temperature X-ray diffraction (HTXRD) and Rietveld refinement of the data obtained at a constant heating rate. While the cell volume increases with increasing Pd as expected by the larger atomic radii, the coefficients of thermal expansion (CTEs) do not follow a uniform trend. The bonding in the basal plane is more elastically rigid than along the c-axis for all compositions. The CTE is more anisotropic for Zr{sub 2}Pd than for Zr{sub 2}Cu, which is consistent with the first-principles calculations that illustrate the rigidity of c-axis relatively to a-axis to be the less for Zr{sub 2}Pd. The CTE of the a-axis for Zr{sub 2}Pd is in fact negative over the temperature range measured.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 970477
• Journal Information: Intermetallics, Journal Name: Intermetallics Journal Issue: 1 Vol. 18; ISSN 0966-9795; ISSN IERME5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
ATOMIC RADII
BONDING
HEATING RATE
SPACE GROUPS
THERMAL EXPANSION
X-RAY DIFFRACTION