Variations in the electrical resistivity and in the deviation from Matthiessen’s rule (DMR) during quench-ageing have been observed on low-carbon aluminium-killed steels containing varied amounts of manganese. The DMR is measured by the difference between the resistivities at 273 K and at the liquid-nitrogen temperature. During the period of violent precipitation of iron-carbides (unidentified carbide, epsilon carbide and cementite), the DMR decreases in the steel containing 0.1 mass% Mn, whereas it increases in the steels containing 0.4 mass%, 0.8 mass% and 1.2 mass% Mn. For the latter three steels, the higher the manganese content, the more marked the increase in DMR. It is deduced from these results that the decomposition of quenched-in Mn–C dipoles occurs simultaneously with the precipitation of carbides. It is further speculated that the solubility of single carbon atoms in ferrite in equilibrium with cementite at 973 K decreases gradually with increasing manganese content, whereas the total amount of carbon atoms contained in ferrite at 973 K, including those combined with manganese atoms to form Mn–C dipoles, increases with increasing manganese content. The binding energy of a carbon atom with a manganese atom is evaluated to be 7.4×10⁻²⁰ J (0.46 eV).

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The thermodynamic factor for interdiffusion in Cu-rich Cu–Zn, Cu–In and Cu–Sn alloys has been estimated by Heumann’s method by use of the experimental data on the tracer self-diffusion, intrinsic diffusion and interdiffusion in these alloys, and the newly determined solute diffusivity in Cu-rich Cu–In and Cu–Sn alloys at 1089 K. The thermodynamic factor is found to be nearly unity in Cu-rich Cu–Zn alloys, but to be smaller than unity in Cu-rich Cu–In and Cu–Sn alloys. On the basis of the values of the thermodynamic factor thus obtained and of the self-diffusivities of both components in these alloys, the vacancy flow term in Darken’s relation as modified by Manning has been estimated. The vacancy flow term in Cu-rich Cu–Zn alloys is found to be consistent with that deduced from Manning’s random alloy model, for which the vacancy flow term is nearly unity. However, in Cu-rich Cu–In and Cu–Sn alloys the vacancy flow term is larger than that deduced from Manning’s random alloy model, suggesting that the attraction between a solute atom and a vacancy in these alloys is highly strong.

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The interdiffusion and intrinsic diffusion coefficients in Ni-rich nickel-tin alloys containing up to 7 at%Sn have been determined in the temperature range between 1223 and 1473 K by use of semi-infinite diffusion couples with the Kirkendall markers. The tracer diffusion coefficients of solvent and solute (or impurity) in pure Ni and the alloys at 1373 K have been determined by use of ⁶³Ni and ¹¹³Sn. On the basis of the present diffusion data on ⁶³Ni and ¹¹³ Sn in pure Ni and the value of intrinsic diffusion coefficient of Ni extrapolated to the infinite dilution of Sn, the vacancy flow factor has been estimated to be −0.86. From the linear enhancement factor of solvent diffusivity and the vacancy flow factor, an appropriate numerical set of the correlation factor and the jump frequency ratios in the five-frequency model has been evaluated. The result suggests highly correlated jumps of a Sn atom to a vacancy in Ni similar to those of Sn in Cu. On the basis of the interdiffusion and tracer diffusion data for the alloys, the thermodynamic factor in Darken’s relation has been calculated by Heumann’s method. The value ofthe thermodynamic factor is found to be less than unity in Ni-rich Ni-Sn alloys, suggesting that Sn atoms have a slight tendency to form clusters. The vacancy flow term in Darken’s relation as modified by Manning has been estimated to be larger than the value deduced from the random alloy model. This implies that the attraction between a Sn atom and a vacancy is highly strong. The concentration dependence of thermodynamic factor and vacancy flow term in Ni-rich Ni–Sn alloys has been shown to be similar to that in Ni-rich Cu–Sn alloys.

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An analysis of the apparent diffusivity of hydrogen in mixed trap and multiple physical trap models was carried out based on the assumption of a system of low occupation probability of hydrogen in a normal lattice and trapping sites and by taking into consideration that the trapping sites have not only the characteristic trap density and depth but also a trap “width” and that the “normal” lattice sites and individual traps have characteristic trapping and release rates.
In this work the diffusivity in a lattice with mixed trap and multiple physical traps can be expressed by closed equations. The theory predicts that the enhancement of diffusivity might occur at low temperature, even if hydrogen is substantially trapped. Such behavior can be explained in terms of an enhanced jump rates due to lower barriers at trap sites compared with those of normal lattice sites. On the other hand, if all the trap sites are already saturated and do not influence the diffusion flux, the resulting diffusion equation is identical with that of McNabb and Foster and that of Oriani.

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The effects of irradiation on the fatigue properties of stainless steel were studied under the condition of in situ irradiation or after irradiation using 20 MeV protons. Strain controlled fatigue tests using a resonant vibration of specimens at about 100 Hz with a total strain amplitude ε_t of (6∼12)×10⁻⁴ were made at 333 K on miniature specimens of solution treated SUS 316. The proton irradiation was made at about 333 K with irradiating current densities of 0.005–0.25 μA/cm² (0.02–1×10⁻⁸ dpa/s). Changes in a vibrational period P and a drive force DF at constant ε_t were measured in situ during the test. Whereas the present damage rate was very low, the apparent effects of in situ irradiation on the fatigue properties were observed, e.g. the elongation of fatigue lives by about twice and the appearance of irradiation hardening for ∼1×10⁻⁸ dpa/s. The changes in fatigue properties observed after irradiation of ∼1×10⁻⁴ dpa were very similar to those obtained for in situ irradiation with ∼1×10⁻⁸ dpa/s. These results are discussed in detail.

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Smooth, adherent coatings of molybdenum can be obtained electrolytically on nickel and copper substrates in KF–Na₂B₄O₇–K₂MoO₄ fused salts at temperatures 998–1173 K and current densities 110–550 A/m² with a molybdenum anode and a graphite anode. The KF–K₂MoO₄ and Na₂B₄O₇–K₂MoO₄ fused salts do not give any deposits of metallic molybdenum.

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The deformation behavior of a crystal containing mechanical twin lamellae has been examined from a view point of deformation geometry, and a two-dimensional model for the nucleation of shear bands has been proposed. It is suggested that in the crystal having (111)[\bar211]^M (+(111)[2\bar1\bar1]^T) orientation, six types of shear localization are possible to occur and two families of shear bands can be nucleated. The shear bands expected show the inclination of about ±20°–35° (0.35–0.61 rad) with respect to the twin lamellae and have the preferred orientation {011} ⟨100⟩ and {211} ⟨111⟩, in agreement with experimental results. The possibility of shear band formation in the other orientation is also discussed.

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A study for production of amorphous alloys by a flame-spray quenching and for their coating to metal substrates was carried out on iron-nickel based alloys. The spray-quenching equipment consisted basically of a thermal spray gun of oxyacetylene type, a metal substrate like copper, and a flame deflector which was employed to deflect partially downward the flame from the gun and water vapor in the flame and to adequately lower the temperature of the flame and spray stream.
Spray-quenched alloy samples were examined to check the progress of vitrification by X-ray diffraction and differential scanning calorimetry. Surface preparation of the substrate face giving proper roughness on it was performed by alumina grit blasting. Tensile adhesion strength of the coating alloy-substrate metal interface was measured by an Instron type-testing machine.
By using the flame deflector as described above, the effectiveness of quenching was greatly increased, and amorphous flakes were easily obtained in quantities in an Fe₃₉Ni₃₉Si₁₀B₁₂ alloy, relatively difficult to vitrify by the spray-quenching equipment without the flame deflector, as well as in all other alloys studied, i.e. Fe₄₀Ni₄₀P₁₄B₆, Fe₁₆Ni₆₄P₁₄B₆, and Fe₁₃Ni₆₄Cr₃P₁₄B₆ alloys. In the Fe₄₀Ni₄₀P₁₄B₆ and Fe₁₆Ni₆₄P₁₄B₆ alloys, whose amorphous flakes were comparatively easy to prepare, amorphous alloy sheets about 450 μm thick were also fabricated by successive building-up of such amorphous flakes on the substrate without difficulty.
By the aid of the present spray-quenching equipment, the amorphous coating about 450 μm thick of each of the Fe₄₀Ni₄₀P₁₄B₆ and Fe₁₃Ni₆₄Cr₃P₁₄B₆ alloys could be applied to both copper and mild steel substrates. Although tensile adhesion strength of the coating-substrate interface for copper was low, the strength for mild steel was about 10–20 MPa and large enough to be comparable to that of the coating system obtained in the ordinary spray process.

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