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Molecular dynamics simulations are used for studying the scattering of phonon wave packets of well-defined frequency and polarization from individual point defects and from a field of point defects in Si. The results have shown that the fractions of transmitted and reflected energies have strongly depended on the frequency of the incident phonons and on the mass and concentration of the defects.

Scanning tunneling microscopy (STM), atomic force microscopy (AFM), and x-ray reflectivity (XXR) was used to investigate the effects of varying tetha(sub H) on surface morphological evolution during Si(sub 0.7) Ge(sub 0.3) growth on Si(001) by GS-MBE at temperatures T(sub s)=450, 500, and 55 degrees Celsius and thinknesses t up to the critical value for misfit dislocations. The differences in surface morphological evolution observed suggests that tetha(sub H) plays an important role in mediating the kinetics of strain-induced roughening through changes in film growth rates as well as adatom mean-free paths and step-crossing probabilities.

A study was conducted to investigate the nanosecond pulsed laser-induced transient melting and miniature surface deformation of Ni-P hard disk substrates. The results show the variation of the feature shape in response to different pulse energies of the near-infrared pulsed nanosecond heating laser beam.

Atomic layer deposition and magnetron sputter deposition were used to synthesize thin-film multilayers of W/[Al.sub.2][O.sub.3]. With individual, layers only a few nanometers thick, the high interface density produced a strong impediment to heat transfer, giving rise to a thermal conductivity of ~0.6 watts per meter per kelvin. This result suggests that high densities of interfaces between dissimilar materials may provide a route for the production of thermal barriers with ultra-low thermal conductivity., Materials with structure on nanometer-length scales are being studied for their promise of providing novel optical, electrical, magnetic, or mechanical properties. The thermal properties of nanostructured materials, however, have received [...]

Abstract: Machining of Ni-based aerospace alloys is one of the major challenges of modern manufacturing. Application of cemented carbide tooling with nano-multilayered AlTiN/Cu PVD coating results in a significant tool life improvement under conditions of turning the hard-to-machine aerospace Ni-based Inconel 718 superalloy. Studies of the structure, properties, tribological and wear performance of the nano-multilayered AlTiN/Cu PVD coating have been performed. The structure of the coating has been investigated using High Resolution Transmission Electron Microscopy. Various properties of the coating including microhardness, thermal conductivity and coefficient of friction vs. temperature were measured. Investigations of the coated tool life, wear behavior and chip formation for cutting tools with nano-multilayered AlTiN/Cu PVD coating were performed. Morphology of the worn tools has been studied using SEM/EDX. AlTiN/Cu coatings present multi-functionality because they combine self-lubricating behavior with reduced thermal conductivity. This beneficial combination of properties results in significant improvement of the coated tool life. [Copyright &y& Elsevier]