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...

Coherent B2-ordered NiAl-type precipitates have been used to reinforce solid-solution body-centered-cubic iron for high-temperature application in fossil-energy power plants. In this study, we investigate the stability of nano-sized precipitates in a NiAl-strengthened ferritic alloy at 700-950 °C using ultra-small angle X-ray scattering and electron microscopies. Here we show that the coarsenin...

Dramatic changes in the surface morphology have been observed during the oxidation of stepped NiAl(16,14,1) by LEED and STM. The initial sequence of identical (110) terraces is lifted in favor of large, triangular planes, whose mean size is determined by the mismatch-induced stress that accumulates in the thin alumina film. The asymmetry of the original step direction on NiAl(16,14,1) with resp...

The oxidation resistant light weight aluminides: NiAl and TiAl with ordered

Chow-Choong Ngeow and Shashi M. Kanbur Astronomy Department, University of Massachusetts, Amherst, MA 01003 Sergei Nikolaev Institute for Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550 Nial R. Tanvir Department of Physical Science, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK and Martin A. Hendry Department of Physics and Astro...

We describe a new Ni5Al3 underlayer for high-density longitudinal magnetic recording. The Ni5Al3 underlayer has the FCC derivative Ga3Pt5 structure. The Ni5Al3 (221) plane has good lattice match with the CoCrPt (10 1 0) plane. In addition, unlike the NiAl (112) plane, the Ni5Al3 (221) plane has the lowest surface energy. Hence, the Ni5Al3 thin film has a strong (221) texture and can induce CoCr...

The internal friction of high-purity NiAl single crystals was investigated utilizing a low-frequency subresonance torsion a p m . Above lOOOK the damping increases strongly up to Q-' =0.3 at 1400K. The activation enthalpy of this viscoelastic relaxation depends on the composition and shows the highest value (2.8eV) for stoichiometric NiAl. The results are discussed in terms of diffusionantrolle...

Platinum is added to thermal barrier coatings (TBCs) as it is observed empirically to extend their lifetime, but the mechanism by which Pt acts is unknown. Since Pt has been proposed to alter diffusivities in NiAl, a key component of TBCs, we use first-principles quantum mechanics calculations to investigate atomic level diffusion mechanisms. Here, we examine the effect of Pt on five previously...

The energetics of Ni vacancy jumps in the intermetallic compound NiAl are studied by combining embedded-atom and first-principles calculations. The embedded-atom potential used in this work is fit to both experimental and first-principles data and provides an accurate description of point defect energies and vacancy jump barriers in NiAl. Some of the embedded-atom results reported here, are ind...

Using the full potential linearized augmented plane wave (FLAPW) method, we have explored the magnetic properties of one dimensional (1D) Ti atomic chain. Astonishingly, we for the first time observed that the 1D Ti atomic chain has ferromagnetic ground state even on NiAl(110) surface although the Ti has no magnetic moment in bulk or macroscopic state. It was found that the physical property of...