A new technique of measuring the X-ray “Pendellösung” intensity beats in white radiations diffracted from perfect single crystals has recently been developed in the authors’ laboratory. In the present work an attempt was made to apply this technique to aluminium using parallel-sided single crystal specimens grown by the strain-anneal method. The atomic scattering factors, f_hkl, for the eight low-order indices were determined from the extremum positions of the measured intensity beats on the basis of the dynamical diffraction theory. The scattering factor shows a linear increase with the wavelength in the range between 0.03 and 0.09 nm, which is attributed to the anomalous dispersion term, f^′, as calculated by Cromer. The absolute atomic scattering factors, f_hkl⁰, are evaluated by averaging the measured values of f_hkl utilizing the Cromer’s f^′(λ) values and temperature factors of exp {−0.8822×10²(sinθ⁄λ)²}. The obtained f_hkl⁰ values were very close to the theoretical ones calculated by the Hartree-Fock method for free atoms and also to those by Arlinghaus and by Cooper and Williams for atoms in crystalline solid.

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In order to examine the initiation of fatigue cracks along grain boundaries, four samples of aluminum bicrystals were tested by a bending fatigue testing machine under constant strain amplitude of 0.2% and cyclic frequency of 30.4 Hz.
It has been confirmed that the initiation of fatigue cracks along boundaries occurs under the following conditions; (a) the planes of the boundaries are {111}, and (b) the slip bands which correspond either to the primary slip system or to the secondary one are remarkably parallel to the boundaries. The fatigue cracks are initiated earlier along these boundaries than along the slip bands in component crystals.

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The (111) surfaces of copper crystals cooled rapidly from 1273 K in a purified argon atmosphere were etched with three kinds of dislocation etchants, and the etch patterns were studied by means of optical and electron microscopies. From the replica examinations with an optical microscope dark and deep etch pits with beaks were found in addition to normal dislocation etch pits. The density of the former pits amounted to 10⁷–10⁸ m⁻², two orders in magnitude less than that of the latter ones. Detailed observations of the replicas with an electron microscope revealed that the beaks extended into the crystal from the base of the etch pits along an oblique ⟨110⟩ direction, though details of their shapes varied with the etching solutions. When the crystal was etched for a long period, the beaked etch pits gradually changed from sharply-pointed and deep ones to flatbottomed and shallow ones, and finally disappeared, while small beaked ones newly appeared at some other places. It is noted that such etch pits could not be observed in slowly-cooled copper crystals. Defect ribbons with a somewhat complicated structure were observed in thin films obtained from the rapidly-cooled copper crystals, which might presumably be associated with the etch beaks.

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The oxidation of cobalt-manganese alloys containing 0–35 mass% Mn was carried out in oxygen at atmospheric pressure at 1073, 1173, and 1273 K . The alloys oxidised according to the parabolic rate law with activation energy of 196 kJ/mol. In general, the addition of manganese up to 17% increases the oxidation rates in comparison with pure cobalt. However, with further addition of manganese the parabolic rate decreases, although in all cases it remains lower than that of pure manganese. The scales formed consist mainly of both cobalt oxide, CoO, and manganese oxide, MnO, with a spinel phase, solid solution of CoO–MnO. With low manganese alloys, 0–17%, the spine1 phase is present as dispersed particles, while in the case of higher percentages of manganese, the spinel was in the form of a continuous layer. In addition to the external scale, internal manganese oxide was noticed and discussed. The increases in the oxidation rate are largely controlled by the extent of the doping effect of the CoO, causing the more rapid metal diffusion in the scale. The decrease in the rate is due to the spinel blocking effect in the oxide.

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The relationship between the Barkhausen noise and the microstructure of a precipitation hardened Co–Fe–Nb alloy has been investigated. The results show that the Barkhausen noise behavior is highly affected by the microstructure of the alloy. In an as-drawn sample with a cold worked dislocation structure, sharply peaked Barkhausen pulses of about 0.5 to 2.0 ms intervals were observed under an external magnetic field rate (dH⁄dt) of 0.64 A·m⁻¹·ms⁻¹. When the alloy was precipitation hardened by aging, large pulses indicative of discontinuous domain wall movements were observed under the same experimental condition. These large pulses are considered to be due to the movements of domain walls interacting with precipitates. On the other hand, saw-toothed waves indicative of relatively continuous domain wall movements were observed for the solution treated sample.
The Barkhausen noise spectra were also measured. The Barkhausen noise level of each sample decreased monotonically with increasing noise frequency. This behavior indicates that the magnetization reversal in the Co–Fe–Nb alloy belongs to the class of Markov processes.

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In the present investigation, effect of 1–4% copper addition on the sintering of Fe–P–Ni, Fe–P–Mo and Fe–P–MCM (Transition Metal Carbide Master alloy, Fe–Mo–Cr–Mn–C) was investigated. The phosphorus in the iron powder was 0.45% while other alloying elements i.e. Ni, Mo and MCM were 1 or 2%. MPIF tensile test pieces compacted at 691 MPa pressure were sintered at 1473 K for 1.8 ks in dry hydrogen. The results showed that copper decreased the shrinkage of all the alloy systems and in some cases zero-dimensional change compacts were obtained. Copper addition invariably improved tensile and yield strengths but decreased ductility of the alloys. The results have been discussed on the basis of diffusivities and liquid phase sintering associated with the presence of both copper and phosphorus.

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