2014 The physical mechanisms governing the equilibrium shape of crystals are described. The roughening transition of a given crystal face is associated with the vanishing of the free energy of a step on that surface. Below the roughening transition, facets of finite size coexist with rounded parts of the surface. Near the boundary of a facet, the shape of the crystal is determined by a fluctuat...

During vapor-phase deposition at 1273 K (1000 C), by pack cementation, of Mo onto 127-lmdiameter Ni wires, two phenomena are observed to occur concurrently, leading to strong surface roughening: (i) the inward radial growth of Kirkendall pores below the wire surface and (ii) the outward growth from the wire surface of protuberances with sizes as large as 15 lm. Highaspect-ratio Kirkendall pores...

We present a modified version of the one-dimensional sine-Gordon model that exhibits a thermodynamic, roughening phase transition, in analogy with the two-dimensional usual sine-Gordon model. The model is suited to study the crystalline growth over an impenetrable substrate and to describe the wetting transition of a liquid that forms layers. We use the transfer integral technique to write down...

The interplay between the contact line elasticity, surface disorder, and dissipation leads to complex and unexpected observations in immiscible flows. Here, we use the Cox–Voinov law to formulate a dynamical evolution equation considering all these effects. We then investigate the roughening transition that occurs in the receding contact lines when the contact line velocity exceeds a critical v...

Using the network etch rate function model, the anisotropic etch rate of p-type single crystal silicon was characterised in terms of microscopic properties including step velocity, step and terrace roughening. The anisotropic etch rate data needed have been obtained using a combination of 2 wagon wheel patterns on different substrate and 1 offset trench pattern. Using this procedure the influen...

We investigate the surface widthW of solid-on-solid surfaces in the vicinity of the roughening temperature Tr. Above Tr, W 2 is expected to diverge with the system size L like lnL. However, close to Tr a clean lnL behavior can only be seen on extremely large lattices. Starting from the Kosterlitz-Thouless renormalization group, we derive an improved formula that describes the small L behavior o...

We study the phase transitions of a restricted solid-on-solid model coupled to an Ising model, which can be derived from the coupled XY-Ising model. There are two kinds of phase transition lines. One is a Ising transition line and the other is surface roughening transition line. The latter is a KT transition line from the viewpoint of the XY model. Using a microcanonical Monte Carlo technique, ...

Grain-scale surface roughening due to plastic straining in polycrystalline aluminum is studied with the aid of a three-dimensional finite-element crystal-plasticity model. An improved understanding of the origin of surface roughening profiles in plastically strained aluminum is sought. Large-scale, Direct Numerical Simulation enables the computation of full-field solutions and the explicit cons...

During spontaneous imbibition, a wetting liquid is drawn into a porous medium by capillary forces. In systems with comparable pore length and diameter, such as paper and sand, the front of the propagating liquid forms a continuous interface. Sections of this interface advance in a highly correlated manner due to an effective surface tension, which restricts front broadening. Here we investigate...

We have begun a collaborative investigation of the response of candidate first-wall inertial fusion energy (IFE) reactor chamber drywall materials to X-rays on the Z facility, and to ions on RHEPP-1, both located at Sandia National Laboratories. Dose levels are comparable to those anticipated in future direct-drive reactors. Due to the 5 /10 Hz repetition rate expected in such reactors, per-pul...