Finite size effects on the thermodynamics of Cu-Ni alloys: {l_brace}110{r_brace} and {l_brace}110{r_brace} thin films

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(96)00234-0· OSTI ID:474189

Swaminarayan, S; Najafabadi, R; Srolovitz, D J ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

A series of atomistic simulations of CuNi{sub 1{minus}x} {l_brace}100{r_brace} and {l_brace}110{r_brace} thin films were performed as a function of Cu-concentration, temperature, and thickness in order to determine the effects of film thickness on the surface concentration and the surface free energy. The surface free energies of these films were found to differ significantly from those of the corresponding flat surfaces of bulk samples. Very thin films exhibit surface entropies {Delta}S which have an opposite sign to those for the bulk (positive surface entropy). These films undergo a transition from negative to positive surface entropy with increasing film thickness, composition and/or temperature. The unusual behavior of the surface free energy of thin films may be accounted for by the surface energy dependence on the surface concentration and the limited solute availability in these systems. Using the prediction of the surface composition and a simulation of a bulk flat surface it is possible to accurately predict the (surface) free energy of thin films as a function of film thickness using only properties of a bulk sample.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-88ER45367
• OSTI ID: 474189
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CONCENTRATION RATIO
COPPER ALLOYS
ENTROPY
NICKEL ALLOYS
PREDICTION EQUATIONS
SIMULATION
SURFACE ENERGY
THERMODYNAMIC PROPERTIES
THIN FILMS