We use molecular dynamics simulations to show that glass transition in a model phase separating amorphous alloy, Cu(50)Nb(50), occurs by gelation. At the glass transition, a mechanically stiff, percolating network of atoms with icosahedral local packing forms at the interfaces between compositionally enriched regions. This low-energy network halts coarsening of the phase-separated structure and...

Deposition of metals on binary alloy surfaces offers new possibilities for guiding the formation of functional metal nanostructures. This idea is explored with scanning tunneling microscopy studies and atomistic-level analysis and modeling of nonequilibrium island formation. For Au/NiAl(110), complex monolayer structures are found and compared with the simple fcc(110) bilayer structure recently...

A phase field model with order parameter, concentration, and temperature as field variables is used to study the properties of solidification fronts in a binary alloy. As in previous papers, the model includes dependence of the free energy density not only on these field variables, but also on the gradients of the order parameter and concentration. Terms with these gradients represent surface f...

A recent experiment @Phys. Rev. Lett. 80, 2141 ~1998!# showed heavily damped excitations in molten Li4Pb, within kinematic scales well beyond those of hydrodynamic sound. These findings pointed to the presence of short-lived out-of-phase atomic motions as the underlying microscopic phenomenon. A series of computer molecular dynamics studies are performed to investigate the details of the atomic...

A multiple-order-parameter mean eld theory of ordering on a binary hexagonal-close-packed (HCP) crystal structure is developed, and adapted to provide a continuum formulation that incorporates the underlying symmetries of the HCP crystal in both the bulk and gradient energy terms of the free energy. The work is an extension of the previous treatment by Braun et al. Phil. Trans. Roy. Soc. Lond. ...

The impact of 11 alloying elements, namely Mg, Ti, In, Sn, Al, Ag, Co, Nb and B, at two nominal concentration of 1 and 3 at.%, and Ir and W, at only a nominal concentration of 3 at.%, on the evolution of texture of Cu was investigated. The behavior of the alloy films was compared with that for pure Cu films. The films were electron beam evaporated onto oxidized Si wafers and had thicknesses in ...

— A proof of existence is given for a stationary model of alloy solidification. The System is composed ofheat équation, soluté équation and Navier-Stokes équations. In the latter, Carman-Kozeny penalization of porous medium models the mushy zone. The problem is first regularized and a séquence of regularized solutions is built thanks to Leray-Schauder's fixed point Theorem. A solution is then e...

Metal membranes play a vital role in hydrogen purification. Defect-free membranes can exhibit effectively infinite selectivity but must also provide high fluxes, resistance to poisoning, long operational lifetimes, and low cost. Alloying offers one route to improve on membranes based on pure metals such as palladium. We show how ab initio calculations and coarse-grained modeling can accurately ...

Alloys based on the near-equiatomic FeCo offer exceptional magnetic properties. The equiatomic alloy was ‘invented’ in 1929, it offers a saturation hardly lower than that of the maximum obtained for Fe-0.35Co, with higher permeability and a lower coercivity than the latter. However, this alloy remained without industrial application, mainly because of its extreme brittleness. Only with the addi...