The magnesium electrolyte such as the MgCl₂–LiCl system has been studied for determining the density and electrical conductivity.
The electrical conductivity of the present system is found to be more than 2.5 to 2.7 times greater than that of the Dow and I.G. electrolytes.
It is possible to reduce the electrolysis temperature of the present system in comparison with the Dow and I.G. electrolytes, and the differences in density between liquid magnesium and electrolytes are about 0.03 to 0.05 g/cm³ for 14.3 to 10.5 mol% MgCl₂.
It is of particular interest that the magnesium is recovered at the bottom of the electrolysis cell in the case of magnesium electrolysis of the MgCl₂–LiCl system.

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Since the Cu–Be alloys have excellent age hardenability, many investigations have been carried out on their characteristics. The X-ray diffraction technique and electrical resistivity measurement were mainly used in earlier work, but recently the use of transmission electron microscopy has contributed greatly to clarify the mechanism of precipitation.
In this study, the Cu–Be alloys were aged for 2 hr at temperatures between 120° and 350°C and the mechanism of precipitation hardening was studied by hardness measurement, optical microscopy and transmission electron microscopy. The results show that the aging sequence of the Cu–Be alloys is α phase→G. P. (I) zone→G. P. (II) zone→γ′ phase→anomalous γ′ phase in the grains and α phase→dilute α phase plus γ phase at the grain boundaries. The γ phase at the grain boundary in both Cu-2%Be and Cu–Be 25 alloys initialy precipitates at the aging temperature of 250°C. Furthermore, the effect of Co on the precipitation hardening was studied by optical microscopy and X-ray microanalysis.

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The aluminium specimens subjected to various cooling treatments were tensile-tested in the temperature range from room temperature to 240°C, in the presence of 3% Zn amalgam.
The yield stresses of these dry specimens increased with an increase in cooling rate. The temperature dependence of the yield stress was almost the same for each specimen, but that of the wetted brittle fracture stress decreased with an increase in cooling rate.
The observed ductile-brittle transition temperature increased with an increase in cooling rate, i.e., the transition temperature of the quenched specimen was higher by 70°C than that of the annealed specimen.
Since the increase in yield stress is due to point defects, secondary defects and thermal stress, the effect of cooling rate on the transition temperature can be evaluated in terms of this sort of hardening, without any interference of interstitial precipitation which is considered to have an important role in the transition of body centered cubic metals.

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An annealed specimen of aluminium was subjected to tensile tests in the presence of Sn–Zn liquid containing 0 to 30% Zn. Pure tin did not embrittle the specimen, but the addition of zinc to tin produced brittle fracture in the specimen at low temperature. With an increase in testing temperature, the ductility was restored. The transition temperature became higher as the zinc content increased, primarily due to the lowering of interfacial energy.
Above 300°C, the grain boundary diffusion became severer and suppressed the ductile elongation. In addition, the grain boundary diffusion tended to shift the transition to a higher temperature.
The dihedral angle became smaller as the zinc content increased. The grain boundary energy also decreased to a large extent due to the grain boundary diffusion during the equilibration treatment.

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To obtain the effect of cold rolling on fatigue strength, commercial 0.8% carbon eutectoid steel was cold-rolled to various degrees of reduction and then fatigued in bending at constant deflection. On the other hand, cold-rolled strips are always accompanied by residual stress, and the fatigue strength is much influenced by the residual stress on the surface of cold-rolled sheets. The residual stress on the surface of the sheet cold-rolled at each rolling rate was measured by the X-ray method (sin² ψ method) which was corrected by Fourie Analysis. The intrinsic change of fatigue strength by cold rolling was obtained using the relation between fatigue strength and mean bias stress. As a result, the fatigue strength increases monotonously with the reduction rate, and the increasing rate of fatigue strength with the reduction rate in the earlier stage of cold rolling, if uncorrected by residual stress, is very large because of the large compressive residual stress.
As an example, the residual stress on the surface of a cold-rolled sheet changes neither by the cold rolling rate of at least more than 10% nor by the one-pass reduction in the range of 1.9%∼4.7%.

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Aging kinetics in Al-1.9 at%Cu and Al-1.9 at%Cu-1.7 at%Mg alloys containing small amounts of Zr, Cr, Mn, Ag and Cd have been investigated by the measurements of electrical resistivity and hardness and also by electron microscope observations.
The addition of Zr, Cr or Mn retards the clustering of solute atoms in Al–Cu and Al–Cu–Mg alloys and then reduces the age-hardening when these elements are finely distributed as the insoluble compounds. This effect can be reasonably explained by a similar mechanism to that of Al–Zn and Al–Zn–Mg alloys, that is, in terms of the increase in vacancy sinks rather than the decrease in supersaturated solute atoms or the existence of binding energy between a solute atom and a vacancy.
The aging kinetics in Al–Cu alloys are little affected by the addition of Ag, despite the well-known fact that Cd reduces remarkably the rate of G. P. zone formation and stimulate the nucleation of intermediate precipitates. This is probably due to the reason that the clustering of Cu atoms takes place on the {100} matrix plane, whereas Ag atoms cluster on the {111} plane and do not participate in the G. P. zones of Cu atoms. The additions of these elements to Al–Cu–Mg alloys decrease the rate of clustering but increase the age-hardening at high temperature. This may be due to the participation of Ag or Cd atoms in G. P. zones of Cu and Mg atoms.

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Influences of contents of Mg (0.2∼0.9 at%) and Si (0.1∼0.6 at%) and additional elements (0.01∼0.2 at%) on the two-stage aging phenomena in Al–Mg–Si alloys have been studied by measurements of hardness and electrical resistivity and electron microscope observations.
Pre-aging at 30°C or 90°C coarsens the precipitate structures in Al–Mg–Si alloys containing more than about 1.1 at% Mg₂Si on artificial aging at 175°C or 200°C, leading to a decrease in strength of the alloys, whereas a refinement of the needle-like precipitates takes place in the alloys containing less than about 0.9 at% Mg₂Si.
The negative effect of pre-aging on Al–1.05 at%Mg₂Si alloy is decreased by additions of Mn, Cr, Zr, V and Fe, but increased by additions of Ag, Cu, Be, Cd and Zn. This may be caused by the fact that the apparent contents of Mg₂Si in the alloys are increased by the latter, but decreased by the former since those additional elements can easily form insoluble compounds with Si and Al atoms.
Based on the obtained results, it is deduced that formation of solute clusters at pre-aging and solute supersaturation by artificial aging play an important role in the two-stage aging in Al–Mg–Si alloys.

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Steady-state creep of pure nickel has been investigated in the stress level 1.0 to 6.0 kg/mm² in argon atmosphere. At high temperatures the apparent activation energy for the steady-state creep, Q_c, is about 66 kcal/mol. At low temperatures Q_c depends on the applied stress, σ. The temperature where the break appears on the Arrhenius plot of the creep rates, \dotε_s, is lowered with an increase in σ. The stress exponent, n, in the equation \dotε_s∝σⁿ, has a tendency to decrease to a value less than 2 in the low temperature region. These results suggest that grain-boundary diffusion creep (Coble, 1963) may become a predominant creep mechanism in this material at lower stress and at lower temperature.

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In order to study the influence of coexisting carbon and nitrogen (C+N) on the flow stress of iron, strain rate cycling tests have been perfomed during the tensile deformation of polycrystalline iron specimens with four different (C+N) contents, 0.005, 0.010, 0.013 and 0.034 wt%, in the temperature range 203°∼373°K. The effective stress and the parameter m^* in the Johnston-Gilman velocity-stress relationship \dotε∝nbσ^*m* on these iron specimens have been determined from the experimental results obtained.
The parameter m^* increases with the increase of carbon plus nitrogen in solution and the effective stress tends to increase with the increase of (C+N) in solution. Therefore, it is supposed that (C+N) serves as a resistance against moving dislocations.
The coefficient of work hardening is scarecely influenced by carbon plus nitrogen.

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Grain boundary sliding and deformation of zone near grain boundary at various constant temperatures under constant load were observed in high-purity aluminium bicrystals and Al–Cu solid solution bicrystals, and then sliding at grain boundary during a constant rate heating under various constant compressive stresses of 20 to 35 kg/sq.cm were observed in high-purity aluminium bicrystals. The grain boundary sliding vs. time curve changes stepwise in the constant load test. When the amount of sliding increased, it was apparent that the sliding was accompanied by shear deformation in the narrow region adjacent to the boundary. It is considered, that the grain boundary migration is caused by the recovery of the deformation in the band region adjacent to the boundary. The addition of 0.2% Cu greatly affected the grain boundary sliding of pure aluminium, but the addition of 0.2∼0.5% Cu did not. The grain boundary sliding during the free compressive deformation was caused by the misorientation of the component crystal for external stress, and it has primarily no relation with the compressive stress on the whole. The activation energies for grain boundary sliding were calculated from the slope of the straight lines in the relative figure of temperature vs. sliding rate at the initial stage of the sliding. The behaviour of the deformation layer in the region adjacent to the grain boundary affected strongly the difference in activation energy for the grain boundary sliding by the compressive direction.

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The surface region of abraded Cu–Al alloys was studied by X-ray diffraction and electron microscopy observations, and electron microprobe X-ray analysis. It was shown that the rubbing of the surface resulted in an increase of stacking fault energy. A weak diffuse scattering due to the creation of short range order was also observed. It has been concluded from these results that the observed increase of intensity of Al–Kα radiation in the surface layer is linked to the tendency of migration of solute atoms toward the surface with the movement of dislocations, resulting in the formation of ordered clusters around them.

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The blue-brittle behaviour of a mild steel in torsional deformation was examined at strain rates of 1.1×10⁻³, 3.4×10⁻², 3.1×10, 9.0×10 and 1.8×10² sec⁻¹ between room temperature and 700°C.
The temperature of the maximum flow stress and the temperature of the minimum strain to failure increased with increasing strain rate. The former was lower than the latter at the lower strain rates of 1.1×10⁻³ and 3.4×10⁻² sec⁻¹, while at the higher strain rates both of the temperatures were nearly equal.
The relation between the strain rates and the testing temperatures of the blue-brittleness depends not only on the diffusion coefficients of nitrogen and carbon in α iron, but also on the concentrations of nitrogen and carbon in it.
At the higher strain rates, the test piece was heated by the dissipated mechanical energy and the blue-brittleness appeared at a rather low temperature.
The blue-brittle behaviour at the lower strain rates, which was observed below about 350°C, may be mainly due to the strain aging by nitrogen atoms.

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