Summary: Adhesion, stability, and bonding at metal/metal-carbide interfaces: Al/WC
Donald J. Siegel
Department of Physics, University of Illinois at Urbana-Champaign,
1110 West Green St., Urbana, IL, 61801.
Louis G. Hector, Jr.
GM Research and Development Center,
30500 Mound Rd., P.O. Box 9055, Warren, MI 48090.
James B. Adams
Chemical and Materials Engineering Department, Arizona State University,
Tempe, AZ 85287-6006.
(Dated: July 16, 2001)
We examine the relative stability and adhesion of the polar Al(111)/WC(0001) interface using Density Func-
tional Theory. Relaxed atomic geometries and the ideal work of adhesion were calculated for six different
interfacial structures, taking into account both W- and C-terminations of the carbide. The interfacial elec-
tronic structure was analyzed to determine the nature of metal/carbide bonding. Based on the surface and
interfacial free energies, we find that both the clean WC(0001) surface and the optimal interface geometry are
W-terminated. Although both terminations yield substantial adhesion energies in the range 4≠6 J/mĘ , bonding
at the optimal C-terminated structure is nearly 2 J/mĘ stronger, consistent with an argument based on surface