The relation between smooth tensile properties and plane-strain fracture toughness K_IC was derived semi-theoretically from the energy balance consideration in the necking region of tensile specimens, and the validity of the relation obtained was examined experimentally with the various high strength martensitic steels.
The results obtained are as follows:
(1) The semi-theoretical relation between tensile properties and K_IC of high strength steels can be written as
(This article is not displayable. Please see full text pdf.)
Here, n, k, ε_f and d_f are the work hardening exponent, the work hardening coefficient, the true fracture strain and the diameter of the specimen at fracture, respectively.
(2) For seven kinds of high strength steels in which K_IC is less than 260 kg/mm²·\sqrtmm, the experimental values of K_IC agree comparatively well with the values calculated from the above equation.
(3) The parameter α, which is defined as the ratio of crack nucleation resistance K_IC^* to crack propagation resistance K_IC, appears to depend on the test temperature (or the fractographic percentage of cleavage) as weel as the diameter of the tensile specimen at fracture.

抄録全体を表示

The growth of the modulated structure during aging and the influence of the growth on the yield strength of aged Ni-10 at%Ti alloy were investigated. The wave lengths and amplitudes of the modulated structure were obtained from angular distances between the side band and the matrix reflections and from the ratio of reflection intensities of the side band to the main reflection, respectively. The results obtained are as follows: (1) The wave lengths and amplitudes of the modulated structure increase with aging, and the compositional distribution pattern of solute atoms in the structure changes from sinusoidal to rectangular waves. The rich regions in the structure change to the γ′ phase continuously. (2) Changes of yield strength with aging are explained by the internal strain due to the lattice modulation and the volume fraction of the Ti rich region in the modulated structure.

抄録全体を表示

To clarify the anodic reaction mechanism of copper-sulfide and chalcopyrite in acidic solution, measurements of the electrode potentials and the anodic polarization curves, and the galvanostatic anodizing were carried out. From the experimental results obtained, the following became clear: (1) The electrode potentials of copper-sulfide and chalcopyrite were more positive than that of the each component metal, and this agrees with the general tendency already given. (2) Both sulfides were anodically dissolved in sulfuric acidic solution, and the sulfur of sulfides was mostly oxidized to elemental sulfur according to the following equation, respectively:
(This article is not displayable. Please see full text pdf.)

抄録全体を表示

The stability against the rolling deformation of the {101}⟨\bar121⟩ orientation which is one of ideal orientations of the rolling textures for fcc metals has been studied through rolling the (101)[\bar121] copper single crystals varying the rolling rates and the references for the rolling direction. The active slip systems and the orientation changes were analyzed by the slip line observation using replica techniques and shape change measurements and by the reflection electron diffraction method, respectively.
In the rolling referred to TD (RD⊥TD reference line), the lattice rotation from (101)[\bar121] to \simeq(211)[\bar111] via \simeq(101)[\bar111] took place independently of the rolling rates. This may be related to the shear deformation in the rolling plane and the stability of the (101)[\bar111] orientation around the rolling direction.
On the other hand, in the rolling referred to LD (RD\varparallelLD reference line), it was found that the (101)[\bar121] orientation is stabilized at a high strain rate rolling (10²/sec), but accompanied by the large orientational fluctuation around the rolling direction at a low strain rate rolling (10⁻¹/sec). The main active slip systems were of about the same kind in both strain rates. It may be inferred from these results that the stabilization of the (101)[\bar121] orientation is due to the self-correcting feature of the active slip systems and the fluctuation is concerned with the dislocation structures (cell and substructure) formed during the deformation under high thermal activation.

抄録全体を表示

The indentations on the cubic plane of Cu single crystals made at 77, 210 and 293°K by the conical indenter were compared with each other. The relationships were studied at 77, 210 and 293°K between the Knoop hardness measured along the various directions on the cubic plane of Cu single crystals and the behaviour of the tensile deformations of Cu single crystals with the tensile axes corresponding to those directions. The summary is as follows:
(1) The shear stress-shear strain curves of Cu single crystals, whose tensile axes were close to the [001]-[011] boundary of stereographic triangle, were obtained at the strain rate \dotε\simeq10⁻²/sec at 77, 210 and 293°K.
(2) At a lower temperature, the slip traces of the indentation generally showed less wavy appearance and were developed more remarkably along about ⟨100⟩ directions from the center of the indentation.
(3) The orientation dependence of the Knoop hardness on the cubic plane of Cu single crystals was discussed in terms of the behaviour of the tensile deformation of Cu single crystals with the corresponding tensile axes. The temperature dependence of the resistance to indenting deformation seemed to vary with the directions of the short diagonal of the indenter on the cubic plane.
(4) According as the deformation temperature was changed, there was a linear relationship between the Knoop hardness along each direction on the cubic plane and the τ_III value of Cu single crystals with the tensile axis corresponding to that direction.

抄録全体を表示

The mechanical anisotropic properties of Ti, Zr and Zircaloy-2 sheets have been measured under a uniaxial stress condition in the temperature range −196 to 300°C. The results obtained may be summarized as follows:
(1) The planar anisotropy of the proof stress and the flow stress at a small strain could be explained in consideration of the Schmid Factor. The invalidity of the Schmid Factor at large strain is due to anisotropy of work hardening.
(2) The n value and the uniform elongation of the specimen cut parallel to the rolling direction are always larger than those of the specimen cut parallel to the transverse direction, except in the case of Zr at −196°C. But the reduction of width at the point of fracture behaves conversely.
(3) It seems that the occurrence of deformation twinning at −196°C leads to the highest valve of uniform elongation and n value in Ti sheets under the condition tested, and also to the linear relation between stress and strain.

抄録全体を表示

The deep drawability of titanium sheets were estimated using the single blank deep drawing method. The results obtained may be summarized as follows:
(1) The limit of drawing ratio (L.D.R.) increases at a nearly constant \barn with increase in \barr. When \barr is kept constant (∼3.5), the result that L.D.R. increases with increase in \barn was obtained. But this seems outwardly from the fact that \barn is related to grain size, and that the specimen with a different grain size workhardens in a different way.
(2) As for the r values of the specimen with the main component of the texture (0002)±35°TD ⟨1010⟩, r₉₀>r₄₅>r₀. The trend of the planar anisotropy of the r value could be explained from the calculation based on the Schmid factor for prismatic slip to the above texture. Their absolute values, however, should be obtained by applying the method proposed by Nagashima et al. to all the possible slip system and twin systems.
(3) It is possible in the cold rolled state to obtain the sheet which has some amount of the (0002) texture component. But when annealed, the basal pole inclined gradually at 30°∼35° to the transverse direction. Therefore, one could not get the texture suitable for texture hardening by the adjustment of the final rolling reduction and the final annealing temperature.
(4) The fracture of the cup wall occurred at 0° position when the titanium sheet was deep drawn, which could be explained by Yamada’s analysis.
(5) The deep drawability of titanium sheets could not be estimated from the X value proposed by Yoshida et al. because in titanium the way of workhardening, the n value and the \barn value vary with grain size.

抄録全体を表示

The assumption that the ear formation of titanium sheets occurs at the position where circumferential compressive stress has the maximum value, leads to the following conclusions:
(1) Under plane strain condition, ear and trough appear at 0°, 45° and 90° to the rolling direction. The ears (troughs) at 0° and 90° have the same height (deepness). The position where ears are formed is anticipated with Jinma’s C value.
(2) Under plane stress condition, two cases, stress ratio n=0 and n=1, are considered.
\ oindentn=0: Ears and troughs appear at 0°, 90° and α to the rolling direction where tan²α=(N−F−2H)⁄(N−G−2H). When four ears are formed, the ear height (trough shallowness) at 0° or 90° is proportional to its reciprocal r value.
\ oindentn=−1: Ears and troughs are formed at 0°, 45° and 90° to the rolling direction. Ear height (trough shallowness) is proportional to the reciprocal r value. The earing formation of titanium sheets used in this experiment could be explained under this condition.
(3) When ears and troughs are formed at 0°, 45° and 90°, the position where ears appear, is anticipated approximately with Δr.

抄録全体を表示

Crystal growthes of the II-IV-V₂ group semiconducting compounds ZnGeP₂ and CdSiP₂ were carried out by a direct melting method and a solution growth method, respectively. The optical properties were chiefly investigated for the obtained crystals.
By a solution growth method with the Sn bath, under the condition of 22 mol%CdSiP₂ concentration and 2°C/hr cooling rate, the CdSiP₂ single crystals with approximate dimensions of 6×2×1 mm³ were obtained. The resistivities at room temperature for the compounds are the large values of the order of 10⁶ Ω-cm (ZnGeP₂) or 10³ Ω-cm (CdSiP₂). According to the results of measurements of the absorption coefficients in the range from room temperature to nearly liquid nitrogen temperature, the fundamental absorptions for these compounds are considered to be of indirect transitions. The energy gaps at room temperature are 1.81 eV (ZnGeP₂) and 2.21 eV (CdSiP₂), and they show linear temperature dependences with gradients −5.3×10⁻⁴ and −8.4×10⁻⁴ eV/deg, respectively.

抄録全体を表示

Dispersion-strengthened alloys, Cu-1.6 vol%TiO₂, Cu-5.1 vol%Al₂O₃ and Cu-1.4 vol%MgO were prepared by the internal oxidation method. And the mechanical properties of the alloys after annealing in argon or hydrogen atmosphere were investigated.
In the treatment in an argon atmosphere, Cu-MgO and Cu-TiO₂ alloys decreased in strength but increased in elongation when the annealing temperature exceeded 600°C. Cu-Al₂O₃ alloy, however, showed as internally oxidized strength even after it was annealed at 1000°C for an hour.
In a hydrogen atmosphere, Cu-MgO and Cu-Al₂O₃ became brittle at the annealing temperatures over 300°C. Cu-TiO₂ alloy began to be brittle at 600°C, and exhibited its minimum in strength and elongation through one hour annealing at 800°C. The alloy, annealed at higher temperature, increased its strength and elongation again.
Some experimental investigations were made with Cu-Al₂O₃ alloy to study the cause of brittleness caused by the annealing in a hydrogen atmosphere. The mechanism of the brittleness may be as follows. In the internal oxidation, CuAlO₂ and CuAl₂O₄ were formed on the grain boundaries of copper matrix and in the hydrogen annealing over 350°C, the double oxides were decomposed into α-Al₂O₃, γ-Al₂O₃ and copper, which contributed to the weakening of the boundaries of copper phase.

抄録全体を表示

The plate specimen of 18-8 austenitic steel was fatigued by the cyclic bending fatigue testing machine, and the dislocation structures beneath the specimen surface and around the fatigue microcrack were examined through the transmission electron microscope operated at 100 kV. Based on the experimental results the fatigue crack initiation was discussed. The main results obtained are as follows:
(1) The dislocation arrangement beneath the surface of the specimen fatigued at a low stress amplitude is closely related to the surface deformation markings. Namely, the dislocations array in the same form as that in single or multiple slip lines. On the other hand, the cell structure formed at a high stress amplitude has no correlation with surface markings.
(2) The densely concentrated dislocations and stacking faults align along the {111} trace in the localized region just beneath the surface, and this structure represents the underlying structure of the persistent slip band. On the other hand, the ladder structure might be formed in such a region of about 20 μ beneath the surface. The fatigue crack initiates in this area.
(3) The well-defined cell structure is formed in the vicinity of fatigue microcrack, and the fatigue crack runs along the {111} trace independently of the cell wall.

抄録全体を表示

The ageing characteristics of quenched Mg-1.3 wt%Ce alloy were studied by electron microscopy and hardness measurement. On isothermal ageing at 150°C, precipitates appeared first on the grain boundaries and dislocations at an early stage and precipitation within grains followed a little later. On ageing at temperatures higher than 200°C, precipitation on the grain boundaries, dislocations and within grains took place simultaneously at an early stage. The diffraction effect observed in the present experiment suggests that the precipitates formed and dispersed uniformly within the matrix at an early stage of ageing were to be of an intermediate phase in which cerium atoms might be enriched on (10\bar10) planes of the matrix. On a later stage of ageing, the precipitates transformed into the equilibrium hexagonal phase of β, ribbon shaped, with the following orientation relationship with the matrix;
(This article is not displayable. Please see full text pdf.)
The ribbon shaped precipitates grew mainly in the direction of ⟨0001⟩ and, in much less extent, in the direction of ⟨11\bar20⟩ of the matrix. Significant age hardening observed in the present alloy should be associated with the precipitation of fine particles dispersed uniformly in the matrix. A certain amount of the intermediate precipitates appeared to remain even on a stage on which the maximum hardness was attained. An activation energy for age hardening process was determined to be 30 kcal/mol.

抄録全体を表示

Chromium diffusion coating, such as the Cr powder pack process using chlorides, brings specimens an increase in weight and size. This facts suggest that the position of the specimen surface moves due to Cr deposition on the specimen surface during the coating treatment. Therefore it is supposed that the formation of diffusion coated layer is controlled mainly by the diffusion coefficient of Cr in the substrate, the Cr deposition velocity on the specimen surface, and the diffusion coating time. In the present work, Cr concentration profiles in the diffusion coated layer were calculated approximately according to Fick’s law under a boundary condition that the position of the specimen surface moved with time, and, the changes in surface Cr concentration were explained reasonably. The calculated results were recognized experimentally, too, by electron probe micro-analysis of the chromium diffusion coated layers.

抄録全体を表示

The Born-Green equation has been analyzed numerically to derive the effective interionic potentials from the structural data observed by X-ray or neutron diffraction experiments for molten metals (alkali metals, Mg, Zn, Hg, Al, Ga, In, Tl, Sn, Pb, Sb and Bi) using a linearized simultaneous equation method. In all the cases the temperature insensitive long-range oscillatory type potentials were found. The damping-behaviour of the oscillations for molten Sb and Bi remarkably deviates from that for the usual metals such as Na. For most of the metals the wavelength of the oscillations observed in this work is moderately in good agreement with that expected from the electron theory of metals. The self-diffusion coefficient, viscosity coefficient and surface tension were calculated using the effective interionic potentials obtained in this work. Adequate agreement with experiments was found.

抄録全体を表示

The effects of Be content (0∼1.7 wt%) and Fe content (5∼20 wt%) on properties in semihard magnetic alloys in the Co-Fe-Be system were investigated. Magnetic properties, resistivity, X-ray diffraction and tensile strength were measured in the specimens annealed at 400∼1000°C after cold drawing by 90% reduction in area.
The results obtained are as follows:
(1) In the wire involving Be, the coercive force is raised to a maximum value by the annealing near 600°C. The maximum value increases with the increase in Be content and reaches about 35 Oe at 1.7 wt%Be. In this case, the squareness ratio is higher than 0.90 and the magnetization is about 14000 G. Moreover, the coercive force tends to increase with the increase in Fe content.
(2) The transformation of the γ phase (fcc) to the α phase (bcc) by cold drawing becomes larger in scale with the increase in Be or Fe content. The α phase, however, is again transformed into the γ phase by the high-temperature annealing.
(3) The high value of coercive force and the high value of squareness ratio even after the high-temperature annealing in Be-involving alloys are attributed to the precipitation of the intermetallic compound CoBe.

抄録全体を表示

The aging characteristics of Cu-30%Ni-Be-Si alloys containing both Be(0.4∼0.5%) and Si(0.3∼0.6%) were investigated by means of hardness tests, optical microscopic observations and micro-beam X-ray diffraction. The results obtained were as follows:
(1) These alloys showed superior mechanical properties (hardness and Kb value) than Cu-30%Ni-Be alloy, and the maximum hardness values of these alloys increased with the addition of silicon.
(2) It is shown that the age-hardening of these alloys is due to the precipitation of NiBe (γ phase) at an earlier stage of aging and due to the precipitation of Ni₃Si (β₁ phase) at a later stage of aging.
(3) By addition of silicon, G.P.zone was stabilized for a long period, the formation of non-equilibrium phase γ′ (or γ″) was retarded and the grain boundary reaction was supressed.
(4) The qualitative relationship was observed between the width of the nodule (the discontinuous precipitates) at grain boundaries and the orientation difference angle of the neighbouring crystals. The width of the nodule became wider with the increasing orientation difference angle of the neighbouring crystals.

抄録全体を表示

The strain gauge factor K at room temperature, the electrical resistivity ρ at 20°C, its mean temperature coefficient C_f and the mean thermo-electromotive force relative to copper E_mf in the temperature range 0 to 40°C have been measured with the cylindrical wires of Fe-Co-Mn alloys in a cold worked state of about 94% reduction. It has been found that the maximum value of K is 5.4 in Fe-Mn binary alloy containing 30%Mn and decreases gradually with increasing Co content, the non-magnetic γ phase alloys showing the values of more than 4.0. ρ of Fe-Co binary alloys increases monotonously with the addition of Mn, while their E_mf shifts from a negative to a positive value with increasing manganese content. C_f of Fe-Mn or Fe-Co binary alloys decreases with increasing Co or Mn content, respectively. Fe-30%Co-45%Mn alloy which exibits the minimum C_f of 2.4×10⁻⁴ show K of 4.6, ρ of 98 μΩ-cm and E_mf of +0.2 μV/°C.

抄録全体を表示

The present paper describes the dependences of tensile ductility properties of single crystals grown from a commercially pure aluminium upon temperature and strain rate. Under several strain rates ranging from 1.2×10⁻³ to 90/sec, simple tension tests were carried out at −196°C, −78°C, room temperature and 100°C. Main results obtained here are summarized as follows:
(1) The total elongation-temperature curve found in a quasi-static tension has a deep dip around about 0°C irrespective of axial orientation of specimen. In a tension at a higher strain rate such as 90/sec, however, the dip disappears as the result of a considerable increase in elongation at −78°C and room temperature. The elongation at 100°C is not affected by the rate and that in the high rate tension is surprisingly small at −196°C. Although a similar situation as mentioned above has also been observed in a tension with the polycrystal from which the crystal was grown, the dip encountered at the slow tension for the present crystal is narrower and situated at a temperature lower than that reported previously for the polycrystalline specimen, and the temperatures at which the elongation is independent of strain rate are found at lower temperatures for the crystal compared with those for the polycrystal.
(2) The total elongation at a given temperature and strain rate is much larger for the crystals with orientations near [110] than for those with orientations near [100]-[111]. On the other hand, at a given temperature except −196°C, the amount of increase in elongation with strain rate is, contrary to the orientation dependence of the elongation itself, larger for the latter crystals.
(3) A local strain measured on a necked-down portion of the specimen fractured at room temperature is larger in the high rate tension than in the quasi-static one. In addition, with increasing strain rate, a strain on a portion other than the necked one is not changed essentially for the specimens with orientations near [110], but is considerably increased in the specimens having orientations near [100]-[111]. The above-mentioned strain rate dependence of the local strains along the axes of specimens fractured at room temperature corresponds to the larger increase in total elongation for the specimens with orientations near [100]-[111] than for those with other orientations.
(4) The total elongation measured at −196°C drops abruptly beyond the strain rate of about 1/sec as observed already in the elongation for the polycrystalline specimen at the same temperature. This abrupt drop of the elongation is caused mainly by the decrease in elongation after occurrence of necking, i.e., the decrease in local elongation. Such a decrease in the local elongation is discussed to happen at an adiabatic tension associated with facts that, at a low temperature such as −196°C, the aluminium has a very small specific heat and its flow stress decreases rapidly with a small rise in temperature.
(5) The slip line patterns were very insensitive to the strain rate for the present commercially pure aluminium compared with the patterns for the high purity aluminium in which they have been well established to be varied sensitively with the rate. Therefore, no difference was found between the patterns observed on the surfaces of specimens pulled at rates of 1.2×10⁻³ and 20/sec, respectively.

抄録全体を表示

PDF参照 （誤）Fig. 9 （正）[PDF参照]

抄録全体を表示

PDF参照 （誤）Fig. 5 （正）[PDF参照]

抄録全体を表示