It is well known that plastic deformation at the tip of a notch or defect influences the brittle fracture in structural steels. Recently the COD (crack opening displacement) concept has come to be applied for the brittle fracture initiation of low and medium strength steels, attaching great importance to research for the influence of the condition at the tip of a notch on the brittle fracture initiation of steel. In this study, the effect of preloading on the fracture strength was studied using notched specimens of low strength structural steel (SM 50). Standard Charpy V specimens were preloaded up to a general yield load by 3 or 4-point loading and then fractured by 3 or 4-point loading at various strain rates at liquid nitrogen temperature. The influence of preloading appeared in specimens which had been preloaded so that their notched surface might be subjected to tensile stress, and their fracture loads tended to increase with preload. However, the specimens which had been preloaded so that their notched surface might be subjected to compressive stress, was not apparently influenced by preloading. The above-mentioned results indicate that the residual stress as well as the plastic deformation at the root of a notch influences the fracture strength of the notched specimens.

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The phase transition of Ag₂In was investigated by means of X-ray diffraction, measurements of specific heat and electrical resistivity, and the composition dependences of lattice parameter and electrical resistivity of the ζ phase (high temperature form of Ag₃In) were also examined over the range of 25–40 at %In. It was found that (1) the Ag₂In phase transformed from the γ-brass type to hcp structure at 222°C with a heat of transition of 130 cal/g-atom, and that (2) the lattice parameter, and the electrical resistivity and its temperature coefficient changed abruptly at 33.0 at %In in the homogeneous region of ζ phase.

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A new ordered structure of Au₅Sn is determined by X-ray and electron diffraction using single crystals. The unit cell of the hexagonal superstructure contains 15 Au and 3 Sn atoms, having the lattice constants a=\sqrt3 a₀ and c=3 c₀, where a₀∼2.94 Å and c₀∼4.78 Å are those of the fundamental hcp cell. The closest interatomic distance of Sn–Sn pairs is \sqrt3 a₀∼5.1 Å, and the displacement of gold atoms from the ideal close packing is evaluated as 0.03₇ Å. The ordered phase transforms to the disordered hcp phase (ζ) at 195°C, and a revised phase diagram of the region of 10–20 at% Sn is proposed.

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Ni–Fe–Nb alloys were vacuum melted, annealed in hydrogen atmosphere over the temperature range 950 to 1350°C and then cooled at various rates from a temperature above their order-disorder transformation points. Measurements of magnetic properties, electrical resistivity and hardness for the alloys showed that the values of initial and maximum permeabilities were highest at approximately 9% Nb and decreased sharply with a further increase in Nb content. In the Ni–Fe–Nb alloy system, the highest initial permeability of 125000 was obtained for the alloy of 79.27% Ni, 11.76% Fe and 8.97% Nb when cooled at 300°C/hr after annealing at 1150°C for 2 hr, and the highest maximum permeability of 580000 for the alloy of 79.19% Ni, 12.16% Fe and 8.65% Nb when cooled at 400°C/hr after annealing at 1250°C for 1.5 hr. The alloy with the highest initial permeability exhibited a coercive force of 2.3 mOe, a hysteresis loss of 2.7 erg/cm³/cycle for a maximum magnetic induction of 5 kG, an electrical resistivity of 74.8 μΩ-cm, and Vickers hardness 207. These alloys have been named Hardperm. The high permeability of Ni–Fe–Nb alloys appears to be due to the removal of impurities, homogenization and grain growth by high-temperature heat treatment and also to the low value of magnetostriction constant in the proper ordering state.

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Two kinds of dislocation configurations have been observed in transmission electron microscope studies of crystals subjected to plastic deformation. One is uniform arrangement of dislocations and the other is cell structure. The former is observed at an early stage of plastic deformation and the latter is usually observed at high plastic strains.
Many different views have been proposed to account for the reason why the cell structure is formed in crystals subjected to plastic deformation. In this paper, this problem is discussed with particular attention to conditions for the cell formation.
(1) The critical dislocation density above which cell structure is formed, (2) the change in dislocation configuration with the growth of cell structure during creep deformation, and (3) the change in average internal stress during creep deformation, were estimated from the calculation based on the following assumptions: dislocations arrange themselves so that the strain rate becomes maximum in creep deformation and so that the applied stress becomes minimum in tensile deformation.
The results of calculations obtained were in fairly good agreement with experimental ones reported hitherto. Therefore, it is concluded that one of the reasons for the cell formation is that dislocations arrange themselves according to the assumptions mentioned above.

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Magnetic properties of Sm₂(Co_1−xAl_x)₁₇ powders with 0≤x≤0.12 have been investigated at room temperature. The crystal structure of these alloys is of the rhombohedral Th₂Zn₁₇ type. The lattice constants a and c were found to increase monotonically with x. The magnetization curves of aligned-powder pellets shows that the decrease of the saturation moment is stronger than that expected for a model of simple dilution of Co moments with non-magnetic Al. In the whole range of x studied these alloys have a magnetically easy c-axis. Approximate values of the anisotropy field and the anisotropy constant were estimated from the magnetization curves. The former increases slightly with x and the latter decreases. Curie temperatures of the alloys were determined by the magnetization-temperature curve measured with a magnetic balance.

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The phase diagram of PbCl₂–ZnCl₂ binary system has been determined by thermal, chemical and X-ray analyses, and the results obtained are compared with the previously reported ones. It is observed that this system has an eutectic at 23 mol% PbCl₂ and 286°C and shows an inflection in the liquidus in the composition range of 40∼50 mol% PbCl₂.
The density measurement has been made for the binary melts by the Archimedean method with two platinum sinkers of different sizes. The density at each composition decreases almost linearly with rising temperature. The molar volume and the thermal expansion coefficient are calculated from the data obtained. It is noticed that the composition dependence of the temperature coefficient of density and thermal expansion coefficient show inflections at about 50 mol% PbCl₂.

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Electric conductivities of PbCl₂–ZnCl₂ binary melts have been measured by using a cell specially designed to have a large cell constant. Viscosity coefficients have also been determined by the oscillating vessel method for the PbCl₂-rich melts and the falling body method for the high viscosity melts. Variation of the ionic species present in the melt with composition has been estimated on the basis of the data obtained. The results are summarized as follows:
(1) Molten ZnCl₂ exhibits very low specific conductivity and high viscosity as compared with other chlorides. This may be attributed to the associating property of ZnCl₂ as previously suggested by others.
(2) Apparent activation energy for specific conductivity decreases with rising temperature, which is particularly conspicuous in the ZnCl₂-rich side of the system, due probably to the thermal dissociation of complex species.
(3) Specific conductivity increases and viscosity coefficient markedly decreases when PbCl₂ is added to ZnCl₂.
(4) Apparent activation energies for both transport properties are decreased by the addition of PbCl₂ to ZnCl₂, but they become nearly constant and show the values similar to those of pure PbCl₂ at the compositions of more than 50 mol% PbCl₂.
(5) It is estimated that the associating property of ZnCl₂ is weakened by the addition of PbCl₂ having a comparatively strong ionic character in the ZnCl₂-rich side and also that single ions become predominant species in the PbCl₂-rich side of the system.

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The magnetic composite wire for memory applications made by the cladding and drawing method has been developed. The origin of magnetic anisotropy in the composite wire was investigated. Magnetic composite wires 0.1 mm in diameter which consisted of CZC (0.80%Cr-0.20%Zr-bal Cu) as the core and Mo-permalloy (81.3%Ni-4.5%Mo-0.4%Mn-bal Fe) as the surface layer 3,4 and 8 μm in thickness were made, and hysteresis loops in the axial and circumferential directions as well as output voltages as the memory element were measured.
In the cold-drawn composite wires there exists strong anisotropy with the easy direction in the wire axis. In the composite wires annealed near 600°C, however, anisotropy with the easy axis in the circumferential direction grows. This anisotropy desirable for memory applications becomes remarkable as the thickness of the magnetic layer decreases. In expectation of strain-induced anisotropy, lattice spacing in the magnetic layer, dilatation of CZC and Mo-permalloy, tensile strength of the composite wires, etc. were measured. In the composite wire with the easy axis in the circumferential direction, the residual stress in the magnetic layer is anisotropic; compressive in the circumferential and tensile in the axial and radial directions.
As the result, it was concluded that the combination of anisotropic residual stress and negative magnetostriction in the magnetic layer favors the magnetization in the circumferential direction.

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The recrystallization and grain growth in cold rolled 3.25% Al–Fe alloy sheets were studied with the specimens of three different sulfur contents.
On primary recrystallization, the textures were chiefly composed of the components found in as-rolled textures being those of (112)[1\bar10], (111)[11\bar2] and (100)[011], and (110)[001], and (100)[001] components were also found as minor ones, in which the (110)[001] component showed a tendency to become strong with increasing sulfur content.
During grain growth, the (100)[001] component seemed to increase preferentially consuming the other oriented matrix components and the ratio of the (100)[001] to the (110)[001] component increased and the value tended to approach a definite value.
It was also made sure that the textures as-rolled and of primary recrystallization of Al–Fe alloys were the same as those of cold rolled 3.25% Si–Fe alloy as well as iron sheets, whereas the main components shifted towards the major (100)[001]+(110)[001] components during grain growth in contrast to those of Si–Fe alloy whose texture was composed mainly of the (110)[001] component.
Heating rate had an influence on the development of texture and the presence of a liquid phase in grain boundaries was assumed in the discussion of grain growth mechanism in the alloy with the sulfur addition.

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The specific volumes were measured by the dilatometric method for liquid tin-silver and antimony-silver alloys. In both systems as well as cadmium- and indium-silver systems studied previously, the molar volumes were found to show slightly negative deviations from additivity around N_Ag=0.6 in order of antimony-, tin-, indium- and cadmium-silver. On the other hand, the volume changes were calculated by Scatchard’s equation with the enthalpy of mixing of these systems. The agreement for these two sets of alloy systems is satisfactory.

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