Epitaxial body-centered cubic Mo and Cr films have been grown on the (111) surface of α–Fe films on Si(111) at 300 and 575 K by electron beam evaporation in ultrahigh vacuum. X-ray diffraction and transmission electron microscopy show that the Mo films are oriented with the (111) plane parallel to the α-Fe(111) plane and with the Mo[1$\overline 1$0] direction parallel to the Fe[1$\overline 1$0] direction in the plane of the substrate. The same orientation relationship holds for the Cr films epitaxially grown on α-Fe(111) surfaces. Epitaxial Fe(111)/Mo(111)/Fe(111) and Fe(111)/Cr(111)/Fe(111) films have also been grown on Si(111). This work provides new examples of low temperature epitaxy which can occur at a substrate temperature as low as 0.1 times the melting temperature of the deposited materials.

The formation of ultrathin (≤20 nm) and smooth CoSi2 layers on c–Si substrates has been studied by using a one- and a two-step RTP silicidation method. Pinhole-free silicide layers with a thickness down to ∼10–12 nm were formed on n−, n+, and p+ crystalline Si substrates in the one-step RTP process by sputtering of Co films as thin as 4 nm and subsequent silicidation at 750 °C for 5 or 30 s. The two-step RTP silicidation method is based on the consumption of only a small fraction of a thick sputtered Co film to form Co2Si or CoSi during a first RTP step at 400–500 °C. A selective etch follows to remove the unreacted Co film. During a second, higher temperature, RTP step CoSi2 is formed. Pinhole-free and smooth CoSi2 films with a thickness down to 20 nm were formed in this way on both n+ and p+ monocrystalline Si substrates.

Ultramicrotomy was successfully implemented for sectioning solder/Cu and composite solder/Cu samples for TEM. Solder/Cu joints, approximately 10 mm by 2 mm by 3 mm, were carbon coated and dipped in cyanoacrylate ester before being embedded into an epoxy mount. The mounted samples were trimmed in a series of steps to obtain a pyramid-shaped, embedded sample with a flat, trapezoidal face of exposed metal for sectioning. Thin sections were sliced directly from the bulk sample using an ultramicrotome and a diamond knife. Once sectioned, the samples were placed on Formvar and carbon coated copper grids for examination by TEM. Solder/Cu joints made with eutectic (63Sn/37Pb) solder and several composite solders, including Cu, Ni, and Cu6Sn5, were examined. For the first time, it was possible to image simultaneously each phase in the material using a single TEM sample. The various phases present in the solder joints, including the Pb-rich and Sn-rich solder phases, the Cu6Sn5 and Cu3Sn intermetallic phases, and Cu were identified using selected area electron diffraction. Artifacts due to sectioning, such as knife marks, intermetallic tearing, and brittle phase extraction, were observed. These artifacts were minimized by controlling the sectioning conditions.

The “x-ray tensile test” is the combination of the standard uniaxial tensile test with x-ray diffraction techniques. In this test, in addition to the mechanical stress-strain values usually obtained from a tensile test, one measures the x-ray strain and stress in the diffracting regions of the sample. In multilayer thin films or in multiphase materials, x-ray diffraction enables the determination of strains and stresses in the individual layers or phases. Correlation of the x-ray data with the mechanical stress-strain values may be used to analyze strain and load partitioning within the specimen. In this paper an extended theoretical analysis of this technique and its application to evaporated Cu films on Ni substrates is presented.

Fission fragment damage was introduced into samples of Bi2Sr2CaCu2Ox and Bi1.7Pb0.3Sr2Ca2Cu3Oy, doped with various levels of UO2, by irradiation with thermal neutrons. The critical temperatures were unchanged. Concurrent with an increase in intragranular Jc previously reported, a decrease in flux creep was observed. The apparent pinning potential for creep at 10 K and 0.8 T increased on irradiation by about two to three times for both the 2212 and 2223 compounds. This increased apparent pinning potential is attributed to the strong pinning introduced by the damage caused by the travel of the fission fragments through the crystal. Pinning potential after irradiation increased with an increase in the amount of UO2 in the sample. The increase in bulk pinning potential on irradiation was proportional to the increase in intragranular critical currents on irradiation, qualitatively as expected theoretically.

The structure of Co/Pd and Co/Au (111) multilayers is studied using transmission electron microscopy and high resolution electron microscopy. We focused on microstructure, atomic stacking (especially at the interfaces), and coherency, as these are structural properties that have considerable magnetic effects. A columnar structure with a strong curvature of the multilayer influenced by substrate temperature during growth is observed. High resolution imaging shows numerous steps at the interfaces of the multilayer structure and the presence of misfit dislocations. In bright-field images, periodic contrast fringes are observed at these interfaces as the result of moiré interference. These moiré fringes are used to study the misfit relaxation at the interfaces, whereas electron diffraction gives the average relaxation over the whole layer. Both measurements determined that, for Co/Pd as well as Co/Au multilayers, 80–85% of the misfit is relaxed and 20–15% remains in the form of strain, independent of the Co layer thickness in the regime studied.

An intermetallic compound c–NiZr and a mixture of elemental powders of nickel and zirconium [Ni50Zr50 (at. %)] have been mechanically ground (MG) and mechanically alloyed (MA), respectively, using a high-energy ball mill in various atmospheres. The products were characterized by x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and chemical analysis as a function of milling time. An amorphous a–NiZr alloy was prepared by both MG and MA in an argon atmosphere. By MG of NiZr, an amorphous nitride a–NiZrN0.15 was synthesized in a nitrogen atmosphere, while a crystalline hydride c–NiZrH3 was formed in a hydrogen atmosphere. On the other hand, ZrN and ZrH2 were formed by MA in a nitrogen and a hydrogen atmosphere, respectively. The amorphization reaction was observed between ZrH2 and Ni by further MA in a hydrogen atmosphere, and a mixture of a–NiZrxHy (x < 1) and ZrH2 was obtained. However, no amorphization was observed by MA between ZrN and Ni in a nitrogen atmosphere. The effects of the milling atmosphere on the phase formations during MG and MA are discussed based on the gas absorption rate.

The deposition of diamond phase carbon films on stainless steel substrates by an ionized deposition technique has been studied. A molybdenum grid used during argon ion sputtering had a decisive role in improving the morphology and adhesion ability of the substrate surface. The chemical composition of the surface was obtained by x-ray photoelectron spectroscopy, indicating the reduction of oxygen, carbon, and other contamination, while the surface morphology of the substrate obtained by scanning electron microscopy showed less roughness with a partially smooth surface. Attempts to extract the deposited films from the pretreated substrate surface by a superadhesive agent with an adhesion of 250 kg/cm2 failed, yielding a much stronger adhesion for the pretreated surface. This fact was also supported by examining the surface morphology, hardness, and the resistivity of the films deposited on the same substrates. As for the crystal structure of diamond phase carbon films on stainless steel, selected area diffraction patterns obtained from transmission electron microscopy suggested a mixture of amorphous carbon and polycrystalline diamond components.

Lattice parameters, microanalysis, and microstructures of phases present in solution treated and aged samples of Ni-9 at. % Sn and Ni-9 at. % Sn-10 at. % Mo alloys have been investigated. Cellular precipitation was observed to occur in both alloys. During the initial stages of transformation the composition of the α-phase constituting the cells did not change with time. However, on formation of secondary and tertiary cells with interlamellar spacings much higher than those of the primary cells, the tin content of the α-phase of the cell decreased continuously with time and approached the equilibrium composition. The loss of supersaturation in the initial stages increased with decrease in temperature. Almost all of the molybdenum remained in the α-phase which contains 6.7 at. % Sn and 10.3 at. % Mo. Very little molybdenum partitioned to the compound which contained 24.9 at. % Sn and 0.40 at. % Mo. The presence of molybdenum considerably decreased the rate of nucleation and growth, reduced the interlamellar spacing, and increased the loss of supersaturation. However, the increase in hardness was observed to be small which is attributable primarily to solid solution hardening.

The structure of SIMOX wafers implanted at 180 keV with doses of 0.1 × 1018-2.0 × 101816O+ cm−2 at 550 °C, followed by annealing over the temperature range of 1050–1350 °C, has been investigated using cross-sectional transmission electron microscopy and a chemical etching. With doses of 0.35 × 1018-0.4 × 1018 cm−2, a continuous buried oxide layer having no Si island inside is formed by high-temperature annealing at 1350 °C. At a dose of 0.7 × 1018 cm−2, multilayered oxide striations appear in the as-implanted wafer. These striations grow into multiple buried oxide layers after annealing at 1150 °C. The multiple layers lead to a discontinuous buried oxide layer, resulting in the formation of a number of Si micropaths between the top Si layer and the Si substrate when the wafer is annealed at 1350 °C. These Si paths cause the breakdown electric field strength of the buried oxide layer to deteriorate. With doses of 0.2 × 1018-0.3 × 1018 cm−2 and of higher than 1.3 × 1018 cm−2, an extremely high density of threading dislocations is generated in the top Si layer after annealing at 1350 °C. The dislocation density is greatly reduced to less than 103 cm−2 when the oxygen dose falls in the range of 0.35 × 1018-1.2 × 1018 cm−2. Here we propose a mechanism that accounts for the threading dislocation generation at substoichiometric oxygen doses of less than 1.2 × 1018 cm−2.

Low-temperature photoluminescence measurements have been taken to monitor the changes in the properties of strained GaAs/InGaAs/GaAs quantum wells grown by molecular beam epitaxy at different substrate (well) temperatures with and without a 90 s-growth-interruption at the heterointerfaces. Sharp exciton peaks with average linewidths as low as 1.7 meV were observed in all the spectra. The spectra from the samples grown employing interrupts were narrower than those without interrupts, indicating structurally improved interfaces. Further linewidth narrowing was also seen in samples employing an additional interrupt of the same duration at the bottom InGaAs/GaAs interface, or by increasing the interrupt time at the top GaAs/InGaAs interface to 180 s. A consistent reduction in the linewidth was also observed in wells grown at higher temperatures. This is most likely due to greater indium re-evaporation leading to a reduction in strain, well width, and interface fluctuations.

Mild steel plates were welded under stationary and dynamic (longitudinal and transverse vibration) conditions. The frequency and amplitude ranges selected were 0 Hz to 300 Hz and 0 μm to 30 μm, respectively. It has been observed on the basis of experimental findings that vibration, in general, reduces the grain size of the weldment, and this reduction is appreciable at a lower amplitude of vibration. This may be due to the lower energy required for nucleation of the solid phase. Fast removal of latent heat of solidification from the solid liquid interface plays a significant part in the grain refinement under vibration.

Sputter-deposited Co–Gd and Cr–Gd multilayer films were studied by high resolution transmission electron microscopy (HRTEM). These two systems are expected to give rise to quite different structures. In good agreement with predictions, the individual Cr and Gd layers were found to be 100% crystalline with sharp interfaces and no noticeable intermixing. Conversely, the Co–Gd multilayer system underwent a solid state amorphization reaction during the deposition itself. This reaction has been found elsewhere to show an asymmetric character with the order of deposition, strong evidence for which is observed in this work.

The role of friction between the microhardness indenter and the test specimen is addressed through the analysis of dry (unlubricated) and lubricated tests on iron by Atkinson and Shi. Quantitative evaluation through a proportional specimen resistance model accurately describes the results. It suggests that friction is a major portion of the observed hardness increase at low test loads, the indentation size effect. The ISE is related to the surface-area-to-volume ratio of the indentation, which is inversely related to the indentation dimension.

Diamond films were deposited on Si substrates by Electron-Assisted Chemical Vapor Deposition (EACVD) using various methane concentrations below 8.1%. It was found that the deposited films were strongly (110)-oriented. This seemed to arise from a high nucleation density of diamond caused by the initial deposition of an amorphous carbon film. A comparison of the graphite etching rate between EACVD and Microwave Plasma CVD (MPCVD) under the standard growth conditions showed that EACVD was able to etch graphite about five times faster than MPCVD. Hence, it was concluded that the differences in the growth rate and morphology between EACVD and MPCVD arise from the different graphite etching rates as well as different chemical species in the reaction gas.

NMR study has been carried out on Ni3Al with B and C additions. The 27Al-, 11B-, and 13C-spectra have been measured as a function of temperature for determining their Knight shifts. The Curie temperature and Knight shift at low temperature in Ni3Al with B and C additions decrease in the order of atomic number of additions, but the Knight shifts around room temperature are nearly the same as that of pure Ni3Al. It is suggested that the addition of B and C affects the electronic structure of Ni, and that B atoms and possibly C atoms occupy the octahedrally symmetric sites neighboring all the Ni atoms.

B-doped diamond films were synthesized by microwave plasma chemical vapor deposition using a mixture of methane (0.5% or 1.2%) and diborane (B2H6) below 50 ppm on either Si substrates or undoped diamond films that had been synthesized using 0.5% or 1.2% methane. The surface morphologies of the synthesized films were observed by Secondary Electron Microscopy, and the infrared absorption and Raman spectra were measured. It was found that when diborane concentration was low, B-doped films preferred (111) facets. On the other hand, high diborane concentrations resulted in a deposition of needle-like material that was identified as graphite by x-ray diffraction.

Vapor-grown carbon fibers (VGCF's) were prepared in a mixture of benzene and Linz–Donawitz converter gas using floating catalytic seeds derived from ferrocene, cobalt acetylacetonate, and thiophene. The diameters of the fibers thus grown were in the range of 2–7 μm. The fibers were heat-treated in argon atmosphere at temperatures between 1700 and 3000 °C. The electrical resistivity at room temperature and magnetoresistance at liquid nitrogen temperature were measured for the as-grown and heat-treated fibers, and morphology of the heat-treated fibers was observed with a scanning electron microscope. The electrical resistivity was nearly similar to that obtained for VGCF's prepared on a substrate in a mixture of benzene and hydrogen. The size effects on the resistivity and magnetoresistance were observed. The magnetoresistance was also found to depend on the heat-treatment time. The magnetoresistance results showed that a transition heat-treatment temperature for the magnetoresistance change from negative to positive was between 2200 and 2300 °C, indicating the graphitizable nature of the present fiber. A characteristic polygonal appearance was observed for the fibers heat-treated above 2500 °C.

Environmental embrittlement of L12-type Ni3(Al, Ti) single crystals doped with 0.05 mass % boron was investigated at room temperature as functions of environmental media and strain rate. Environmental embrittlement occurs in air, water, and hydrogen gas, and is also very sensitive to strain rate with a decrease of elongation with decreasing strain rate. Environmental embrittlement is little influenced by boron doping, indicating no strong interaction with hydrogen in lattice. In embrittled condition, tensile elongation and fracture stress are reduced, and fracture mode is primarily {001} cracking with a river pattern. Based on these results, it is proposed that hydrogen affects lattice bonding and thereby reduces the cohesion strength on {001} atomic plane. Also, it is suggested that the major cause of environmental embrittlement of boron-doped Ni3(Al, Ti) single crystals is due to the reaction of water (i.e., H2O) in environment with the reactive element of Al (and/or Ti) and of H2 in environment with the surface reactive element of Ni.

Strained multilayers composed of two misfitting layers and a third, thin interlayer are considered. With appropriate intermediate lattice parameters for the interlayer, the latter is shown to stabilize the structure with respect to misfit dislocation formation. Cases of misfit corresponding both to balanced biaxial stress and to pure shear stress in the interface are treated.