In situ observation of thermal expansion of tetragonal C11b phase in Zr2Cu(1-x)Pdx alloys
|Title||In situ observation of thermal expansion of tetragonal C11b phase in Zr2Cu(1-x)Pdx alloys|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Xu M, Ye YY, Morris JR, Sordelet DJ, Kramer MJ|
|Keywords||ab-initio, anisotropy, crystal chemistry of intermetallics, crystallization behavior, devitrificati, diffraction, electronic structure of metals and alloys, metallic glasses, thermal stability, total-energy calculations, vegards law, wave basis-set, zr-pd|
The C11b phase crystalline structure (structure type MoSi2, space group 14/mmm) in the Zr2Cu(1-x)Pdx (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 (CFEs) 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 CFE is more anisotropic for Zr2Pd than for Zr2Cu, which is consistent with the first-principles calculations that illustrate the rigidity of c-axis relatively to a-axis to be the less for Zr2Pd. The CTE of the a-axis for Zr2Pd is in fact negative over the temperature range measured. (C) 2009 Elsevier Ltd. All rights reserved.
|URL||<Go to ISI>://000271489900002|