Vibrational entropy of L1(2) Cu3Au measured by inelastic neutron scattering

Article

关键词: SOLID-SOLUTIONS;    ALLOY CU3AU;    DYNAMICS;    PHASE;   

DOI  :  10.1103/PhysRevB.60.3976

来源: SCIE

【 摘 要 】

The phonon density of states of elemental Au, Cu, and Cu3Au with L1(2) chemical order were measured by inelastic neutron scattering and used to calculate the vibrational entropy of formation of the ordered compound from the elemental metals. A vibrational entropy of formation of (0.06 +/- 0.03) k(B)/atom at 300 K was obtained, with the vibrational entropy of the ordered alloy being larger than that of the elemental metals. The phonon DOS of the disordered Cu3Au was simulated by adding the phonon DOS curves of fee Cu, L1(2) Cu3Au, and fee Au to match the numbers of first-nearest-neighbor pairs in a disordered alloy. The vibrational entropy obtained with this simulated DOS disagrees with calorimetric data and theoretical estimates, indicating that the phonon DOS of disordered Cu,Au depends on chemical order at spatial lengths larger than is set by first-nearest-neighbor pairs. [S0163-1829(99)02429-7].

【 授权许可】

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