Fe_1−xTi_x alloy films obtained by rf sputtering technique have been investigated by X-ray diffraction and magnetization measurements. The single bcc phase is extended up to about x=0.18, while the amorphous phase is realized for x>0.2, where the intermetallic compound, TiFe₂ and the ordered phase, TiFe, are stabilized in the equilibrium alloys. The lattice constants of the bcc phase are about 0.5% larger than those extrapolated from the results of the bulk Fe–Ti alloys. In the bcc alloys, the average magnetic moment decreases monotonically with increasing x and deviates downward from the simple dilution law. In the amorphous alloys, magnetic moments are much smaller than those for the metastable bcc alloys. The magnetic moment and the Curie temperature in the amorphous alloys show weak concentration dependence in contrast to their strong concentration dependence in the equilibrium Laves phase, TiFe₂.

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Mössbauer spectra were obtained at 290 K and 4.2 K for the metastable bcc and amorphous phases of the Fe_1−xTi_x sputtered alloys. For x≤0.18 (the metastable bcc phase region), the ferromagnetic sextet was observed at 290 K. A wide hyperfine field distribution and a small hyperfine field component, which appears with an increase in x, imply that the magnetic moment of Fe atoms is dependent on the near neighbor atomic configuration of nonmagnetic Ti atoms. For x≥0.22 (the amorphous phase region), a considerably broadened sextet was observed at 4.2 K. The average value of the hyperfine field for the amorphous alloy with x=0.32 is comparable to that for the Laves phase, TiFe₂. At 290 K, where the amorphous phase is paramagnetic, a quadrupole splitting was detected and its average magnitude is also comparable to that of the Laves phase.

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Studies done on the solidification characteristics of synthetic cast-irons of various purity levels melted and cast under vacuum varying from 13.3 Pa to 1.33×10⁻⁴ Pa bring out certain significant results. Properly degassed clean cast-irons under conductive heat transfer conditions are prone to inverse chill formation. This happens when growth of eutectic graphite terminates at certain undercoolings and further solidification proceeds by cementite nucleation. The shapes of graphites, as revealed by scanning electron microscopy, at the transition zones between white and gray iron, across the inverse chill zone show how the eutectic graphite coarsens into different forms before its growth is stopped. Nodular graphite forms at high cooling rates and coral graphite forms at low cooling rates in high purity cast-irons only. The conditions like purity level, cooling rates and superheat etc., leading to various nodular graphite densities in such cast irons have been identified. Based on this a theory is proposed explaining the mechanism of formation of nodular graphite in such cast irons involving carbides as nucleating agents. Implications of the above studies in the formation of nodular graphite and inverse chill in commercial cast irons inoculated with magnesium are discussed.

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The time-temperature range of the formation of metastable and stable carbides and their rate of growth during the ageing of three grades of low carbon steel containing Si in the range from 0.3 to 1.52 mass% have been studied using TEM. In comparison to steels with higher amount of Si (3 mass% and more), stable carbide particles started precipitating quite early during ageing and at lower temperatures in the investigated steels. Thus, inhibition of the transition of metastable to stable carbide was negligible. The growth-rate of carbide particles for the 0.3%Si steel was appreciable; however, the same for the steels with 1.1 and 1.5%Si was slower. These findings together with the observations on sites of nucleation of the carbides have been rationalised on the basis of the role of silicon in modifying the activity coefficient of carbon in ferrite and the stability of the carbides.

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Internal friction of amorphous Pd₈₀Si₂₀ metal doped with hydrogen or deuterium was measured with a specially designed apparatus using amorphous metal sheet as a part of the electric oscillating circuit. Two peaks in Q⁻¹ curve are observed. Applying the peak shift method to the first “Snoek-like” peak, we can determine the relaxation time from which the microdiffusion coefficient can be calculated. The obtained microdiffusion coefficient is about 10⁻¹⁴ m²/s at 200 K, being comparable with the macrodiffusion coefficient obtained from the releasing method. It can, however, not elucidate the hydrogen isotopic effect on the peak temperature of Q⁻¹ curve, the activation energy for relaxation and the relaxation time from the present work because of the broadness of obtained Q⁻¹ curve.

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The behavior of hydrogen during solidification of pure aluminum has been investigated on the ingots solidified unidirectionally under various growth rates. The results are summarized as follows.
(1) Owing to hydrogen rejected by solid, hydrogen bubbles form ahead of the solid-liquid interface as the solidification proceeds. The situation of the bubble formation alters with the growth rate, therefore the distribution of hydrogen in the ingot also varies with the growth rate.
(2) The distribution of hydrogen shows three typical shapes according to the growth rate. The cause of each distribution is explained in connection with the bubble formation at the solid-liquid interface.
(3) The degassing limit of the freezing out method is nearly equal to the equilibrium solubility of hydrogen in the solid under one atmospheric pressure at 933 K.
(4) The diffusivity of the hydrogen in an aluminum melt of 933 K, obtained from the analysis of hydrogen distribution in the ingot, is 7.8×10⁻⁸ m²/s.

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The graining process and powder metallurgical process were applied to fabricate the CF–Al composite materials. At first, small particles with diameters of around 0.5 mm, consisting of the carbon fibers and aluminium alloy (CF–Al composite particle), were obtained by stirring a mixture of molten Al alloy and chopped carbon fibers until the alloy solidified to form small particles. An attempt to mix carbon fibers with four kinds of metals, i.e. Al, Al–Cu, Al–Ti and Al–Cu–Ti, was tried. Among them, the Al–Cu–Ti alloy was considered to be most suitable for producing the composite particles, presumably due to the improvement of wettability of Al against carbon fiber by adding a small amount of Ti and to expansion of the width between the liquidus and solidus by alloying Cu. The good wettability and lower melting point may provide the advantage to this “graining process” for the fabrication of the composite particles even by a shorter stirring time at lower temperatures compared with plain Al. Therefore, damages caused by the mechanical destruction and chemical reaction between Al and carbon fiber during the stirring process may be decreased. The carbon fibers composing the composite particles were observed as being well covered with thin layers of the alloy.
Pieces of CF–Al composite material were fabricated from these particles mixed with Al powder, compressed into a disk shaped compact and sintered in a vacuum. Their Brinell hardness was 20 to 30% larger than that of sintered Al. However, the bending strength was slightly reduced. The mechanical properties may be improved by choosing Al powder as a bonding substance (stamped Al seemed to be better than atomized Al) with suitable size, shape, chemical composition and the appropriate sintering conditions.

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