An age-hardening was observed in aluminum-2.2wt% lithium alloy specimens irradiated to a neutron dose of 1.2×10¹⁹ cm⁻² at 45°C. The specimens were annealed for 4 hr at 350°C prior to the irradiation. Upon heating at temperatures of 155°, 170° and 191°C, the yield stress of the irradiadted specimens increased in two stages following the recovery of radiation-induced hardening, while the yield stress of unirradiated specimens remained unchanged.
The changes in yield stress of the irradiated specimens can be explained as follows. Precipitate particles in the overaged state were destroyed and resolved into the matrix by the irradiation. And the irradiation temperature was too low for the alloy to proceed the precipitation process during the irradiation. Hardening observed in the as-irradiated specimens was due to lattice defects produced by irradiation. Following the recovery of the hardening, precipitation hardening took place in two stages corresponding to the precipitation of spherical and rod-shaped particles.

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Crystal structures and magnetic properties of Pt–Mn–Sb alloys have been investigated by means of X-ray and magnetic analysis. It has been found that a new C1_b type compound PtMnSb exists in the Pt–Mn–Sb system and forms solid solutions in the compositional range of Pt_1.00Mn_1.00Sb_1.00∼Pt_0.94Mn_1.12Sb_0.94. These alloys in solid solution have lattice parameters of about 6.196∼6.228 Å at room temperature, saturation magnetizations of 62.0∼64.0 e.m.u./g at absolute zero, effective Bohr magneton numbers of 3.73∼4.14 μ_B per Mn atom at absolute zero, and Curie temperatures of 522°∼595°K . The magnetic susceptibility of these alloys has been found to satisfy the Curie-Weiss law above the Curie temperature.

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Measurements of the linear coefficient of thermal expansion, Young’s modulus and its mean temperature coefficient, and density were carried out at elevated temperatures so as to investigate the variation in the Elinvar property of nickel at high temperature with the addition of palladium and platinum. It has been made clear from the results of these measurements that in the Ni–Pd and Ni–Pt systems investigated the high temperature at which the Elinvar property of nickel appears falls down along the magnetic transformation point with increasing additive elements, and also a minimum linear coefficient of thermal expansion which represents the Invar property is observed near a composition in which the Elinvar property occurs.

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Since the discovery of “Malcolloy” having high coercive forces in the system of cobalt and aluminium, investigations have been made on the effect of additions of nickel, molybdenum, titanium, vanadium, chromium, tungsten and manganese on the properties of Malcolloy, the highest coercive force obtained in each system of alloys being 1200∼1600 Oe. In this report, the effect of germanium additions on the properties of Co–Al alloys is examined, with the result that the coercive force of the alloys increases with increasing germanium content. An alloy composed of 81.80% Co, 9.20% Al and 9.00% Ge shows a coercive force of 1600 Oe, a residual magnetic flux density of 4200 G and a maximum energy product of 2.20 MG . Oe when tempered at 500°C for 125 hr after water-quenching from 1310°C. These alloys consist of many ferromagnetic elongated particles about 500∼1500 Å in length which are precipitated in the matrix of the nearly nonmagnetic β′ phase. The results show that the high coercivity of these alloys is mainly caused by the presence of single magnetic domain particles.

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The infrared absorption studies have been carried out on the silicate glasses as an approach to clarify the constitution of molten silicate. As seen in the figures of infrared absorption spectra obtained for the binary silicates of PbO–SiO₂, CaO–SiO₂, BaO–SiO₂, ZnO–SiO₂ and Na₂O–SiO₂ systems, each vitreous silicate gives characteristic spectral curves. From the result of investigation on the absorption band of ν₃ vibration due to Si–O stretching mode, it may be predicted that the different kinds of silicate anion can co-exist in vitreous or molten silicates over a certain SiO₂ content.

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The effects of twenty-one kinds of less than 0.5 at% additional elements and heat treatments on the fracture characteristics of Al-2.5 at% Zn-2 at% Mg alloy were mainly studied by the measurements of tensile properties and resistance to stress-corrosion.
The additions of more than 0.01 at% In and 0.03 at% Cd weaken cohesivity across grain boundaries of Al–Zn–Mg alloy quenched from 465°C. Higher solution temperature and 0.03∼0.1 at% Ag also weaken the cohesivity in the fully aged conditions. The additions of Zr, Mo, V, Cr and Mn improve not only grain boundary embrittlement but the resistance to stress-corrosion when these elements are finely distributed as insoluble compounds and are effective for the refining of recrystallized grains. Slow quenching after solution treatment deteriorates ductility as well as strength, but improves the resistance to stress-corrosion. This may be due to the development of mechanically weak, solute depleted zones along grain boundaries and of the associated wide precipitate-free zones.

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Thermodynamic properties of the liquid binary aluminum alloys have been investigated by various equilibrium measurements. The measurement of the electromotive force was carried out for the Al–In, Al–Sn, Al–Ga and Al–Au systems using the following cells:
Al (l) |NaCl+KCl, AlCl₃|Al–Me (l)
For a part of the Al–Au system, the distribution of gold between the Pb–Au and Al–Au phases was measured to obtain the activity of gold because the emf method was not suitable at temperatures higher than 1000°C. The liquid Al–Zn and Al–Te systems were investigated by the dew point method which was improved so as to detect the dew point thermoanalytically.
The activities derived from the measured values show considerably positive deviations from Raoult’s law for the Al–In, Al–Sn and Al–Zn systems, while in the Al–Ga system obey Raoult’s law fairly well, and show negative deviations in the Al–Au and Al–Te systems. The activity values thus obtained have compared with the previous data and those estimated theoretically in various ways. Moreover, activity coefficients at infinite dilution have also been calculated.
Other thermodynamic quantities of these systems have been derived from experimental data, and the limits of the miscibility gap in the Al–In system, which have not yet been established, was confirmed by the data on the electromotive force observed.

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In order to clarify the basic principle of the Parkes process, in which precious metals are extracted from the crude lead by the addition of zinc, thermodynamic studies have been carried out for the liquid Au–Zn and Ag–Zn systems for which thermodynamic data have not been satisfactorily available. The electromotive force was measured using the following type of the cell:
Zn (l) |NaCl+KCl, ZnCl₂|Zn–M (l)
The error arising from volatilization of zinc was carefully avoided.
The break points on the electromotive force curves against temperature suggest that the liquidus lines for the Au–Zn system recommended by Hansen are not acceptable, and that higher liquidus temperature may be reasonable.
The activity curves obtained from the electromotive force values show considerably negative deviations from Raoult’s law, especially in the Au–Zn system, suggesting the large affinity of zinc for gold and silver.
In connection with the present data obtained, the properties of alloys between groups IB and II have been discussed in terms of the electronegativity, ionic radius and electron configurations. It is proved phenomenologically that the obtained data may be also interesting from the standpoint of recent stability theories of alloy phases.
To understand the principle of the Parkes process, the results in the present study are combined with the data of the Au–Pb and Ag–Pb systems, and the free energy of mixing for the ternary Au–Pb–Zn and Ag–Pb–Zn systems has been calculated. Moreover, the removal limit of the precious metals from lead has been explained under the simplified assumptions.

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The influence of high hydrostatic pressure on the stress-strain behaviour of high-purity aluminium polycrystals at room temperature has been investigated. A magnetostrictive load cell has been employed for measuring loads under hydrostatic pressures. Results obtained are as follows : (1) Pressurizing under a pressure of 15000 kg/cm² has no effect on the flow stress of annealed polycrystals pulled at atmospheric pressure. (2) Tensile tests under constant hydrostatic pressures up to 12000 kg/cm² show that the flow stress at a constant strain increases with increasing pressure. The rate of increase of the flow stress under a constant pressure as compared with that at atmospheric pressure increases with increasing strain and becomes constant above 15% strain. (3) The rate of increase of the flow stress under a hydrostatic pressure as compared with that at atmospheric pressure for the same specimen measured by the differential pressure method is constant over the strains tested. It is a little larger than the rate of increase of the shear modulus of the material due to hydrostatic pressure. (4) The amount of work-hardening for a constant strain increases with increasing hydrostatic pressure. This phenomenon is explained by the decrease due to hydrostatic pressure of both the dislocation mobility and the density of mobile dislocations. (5) A phenomenon that is similar to work-softening is observed for a spceimen which is pulled under hydrostatic pressure, then unloaded and reloaded at atmospheric pressure.

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The Kirkendall shift in Cu/Cu-14.7 at% Al diffusion-couples has been measured at 900° and 1000°C. Self-diffusion coefficients of aluminum, D_Al^*, were evaluated from the results on the Kirkendall shift obtained in the present experiments together with the data on the self-diffusion of copper (Kucera and Million, 1970) and of the interdiffusion (Oikawa et al., 1970) in this solid solution. The ratio, D_Al^*⁄D_Cu^*, is about 2.2 in pure copper and about 1.8 in the Cu-9 at% Al alloy. The ratio of the self-diffusion coefficient in the alloy to that in pure copper is about 1.6 for aluminum, while the ratio for copper is about 1.9.

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Recovery spectra of Mo fast neutron irradiated at 10°K was determined by an electrical resistivity measurement from stage I to stage III.
The effect of radiation doping at room temperature upon the stages I and II recovery was also investigated and it was found that the stages I and II recovery is enhanced by the doping.
The stage III recovery was studied in only doped and in doped and subsequently low temperature irradiated specimens.
The enhancement phenomenon was discussed in conjunction with the stage III recovery study.

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