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Volume 39, Issue 8
Displaying 1-17 of 17 articles from this issue
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Osamu Okuno, Ishi Miura1975 Volume 39 Issue 8 Pages 773-778
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe fiber/fiber interaction in short fiber reinforced composite alloys was studied by the moiré strain analysis. Models were prepared from the Al matrix and one short W fiber which was flanked by continuous W fibers. And these lateral fiber spacings were 18 df, 9 df and 6 df (df: fiber dia., df=0.5 mm). Uniaxial loading parallel to the fiber was considered.
The results obtained are as follows:
(1) Strain concentration in the matrix decreased with reducing lateral fiber spacing and the strain concentration area in the matrix became narrower with decreasing lateral fiber spacing. For example, the lateral effect of strain concentration was about 15 df when the lateral fiber spacing was 6 df and the average strain of composite alloy model was 5.4×10−3.
(2) The maximum value of shear strain in the matrix along the short fiber-matrix interface decayed down as lateral fiber spacing decreased.
(3) The critical aspect ratio diminished from 30 to 20 when the lateral fiber spacings decreased from 18 to 6 df.
(4) In the vicinity of short fiber ends, the strain concentration factor of the nearest fibers was about 1.4 and that of the second nearest fibers was about 1.2 when ec was 5.4×10−3, the lateral fiber spacings being 6 df.View full abstractDownload PDF (442K) -
Osamu Okuno, Ishi Miura1975 Volume 39 Issue 8 Pages 779-784
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe moiré strain analysis is applied to some fiber over-lapping models of short W fiber reinforced Al composites under tension. Four kinds of fiber overlapping models are adopted, that is l0⁄lf=0, 0.25, 0.5 and 1 (l0: fiber overlap length, lf: fiber full length=20 mm). And the transverse fiber spacing is 5 df (df: fiber dia.=0.3 mm).
The results obtained are as follows:
(1) In the case of l0⁄lf=0 or 1, the maximum value of strain and interfacial shear strain concentration factor in the matrix is very large. And these strain concentrations in the matrix rise rapidly as the average strain in a composite is increased.
(2) The best fiber overlap to minimize matrix strain concentration and interfacial shear strain concentration in the matrix is one having 0.25 or 0.5 overlap case. In this case, there is almost no rise in these strain concentrations with increasing average strain.
(3) The fracture of l0⁄lf=1 model and l0⁄lf=0 model initiated by interface shear fracture of matrix fracture near fiber ends at a lower value of applied strain. The fracture of l0⁄lf=0.5 model and l0⁄lf=0.25 model initiated by fiber fracture at a relatively high value of applied strain.View full abstractDownload PDF (628K) -
Osamu Okuno, Ishi Miura1975 Volume 39 Issue 8 Pages 785-791
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFiber/fiber interaction in face to face fiber models of W short fiber reinfoced Al alloys are studied in axial load by using moiré strain analysis. Effects of distance between fiber ends and lateral fiber spacing on fiber reinforced mechanism are investigated.
The results obtained are as follows:
(1) It was found that the interfacial shear strain concentration factor in the matrix increased to a very high value as the distance between fiber ends decreased. And the closer the distance between the fiber ends, the shorter the fiber critical aspect ratio.
(2) Variation in lateral fiber spacing from 18 df to 3 df (df: fiber dia.) showed a decrease in the strain concentration and also in the interfacial shear strain concentration in the matrix.
(3) These concentrations increased as the average composite srain increased.
(4) The strain concentration factor in the neighboring fiber near face to face fiber at 3 df lateral fiber spacing and 0 distance between the fiber ends was about 1.4.
(5) Both the face to face fibers and the fracture fiber almost equally affected neighboring fibers and the matrix.
(6) As the load increased, fiber fracture initiated randomly. When these fiber fractures occurred in close proximity, these fiber fractures propagated to their neighboring fibers and finally composite failure occurred at a right angle to the fiber.View full abstractDownload PDF (756K) -
Hajime Suto, Jin Onuki1975 Volume 39 Issue 8 Pages 792-800
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to determine the optimum aging temperature to give superior toughness to an age-hardening alloy, a comparison of the experimental values of ductility in the under- and over-aged states having similar strength was made using various kinds of iron and aluminum alloys, for example, Fe-Cu, Fe-Cr, Fe-Ni-Cu, Fe-Ni-Mo-C, Fe-Co-Cr-W, Al-Si and Al-Ag alloys. The following conclusions have been drawn from the data by the authors and other investigators: (1) In general, the under-aged alloy has a higher ductility, a lower yield point and a larger strain hardening exponent than those in the over-aged alloy having similar tensile strength. (2) In the alloys strengthened by precipitation of G.P. zone or by decomposition into two phases, in other words, having a coherent second phase, premature fracture often takes place in the under-aged state. (3) In the heavily cold worked alloys and secondary-hardened high alloy steels, the superior toughness may be obtained after slight over-aging.View full abstractDownload PDF (976K) -
Shotaro Morozumi, Shoji Goto, Yasoji Tsukaue, Hideo Kayano1975 Volume 39 Issue 8 Pages 801-808
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements of electrical resistivity and mechanical property, and microscopic observation were carried out in order to clarify the role of carbon in the annealing hardening of neutron-irradiated vanadium specimens containing various amounts of carbon.
The results obtained are as follows:
(1) Two peaks appeared in yield stress-annealing temperature curves of the specimens irradiated to 3.4 and 4.7×1020 neutrons/cm2 (>1 MeV) and annealed for 1 hr at various temperatures: The first one is at about 200°C and the second is at about 500°C.
(2) The first peak increased in height and shifted slightly to lower temperature side with increase in carbon content. Correspondingly, the isochronal recovery curve of electrical resistivity also shifted to lower temperatures with increase in carbon content. However, there was no significant change in the microstructure with annealing temperature up to 300°C, and the structure was characterized by a high density of very fine and irregularly-shaped defects.
(3) The second peak extremely increased in height with increase in carbon content, but did not shift. The defect clusters changed to dislocation loops above 300°C and decreased their density with increase in annealing temperature.
(4) It was considered that the first peak was caused by segregation of interstitial impurities dissolved in the matrix to the defect clusters, and that the second was by the dislocation loops reinforced with segregated carbon atoms which came out at annealing temperatures by decomposition of cabide pre-existed at lower temperatures and probably precipitated again around the loops by cooling to the ambient temperature.View full abstractDownload PDF (953K) -
Yoshio Hasegawa, Shinsaku Hanasaki, Masanori Yasutomi1975 Volume 39 Issue 8 Pages 809-817
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper describes the cutting mechanism of large crystals of Fe-3.5%Si crystallographically. The experiment was conducted under the two-dimensional cutting. The large crystals (average diameter is about 5 mm) were produced through the strain anneal method. The orientation of the crystals were determined by the Laue X-ray back reflection method.
The main results obtained are as follows:
(1) In spite of two dimensional cutting, the side force (force component acting in direction normal to the side plane of a workpiece) occurs because the slip deformation takes place three-dimensionally.
(2) The cutting force and the chip formation mechanism are divided into three types according to the difference in the orientation of crystal against the cutting direction;
(a) Cutting force is stable and continuous chip generates without built-up edge.
(b) Cutting force and chip thickness increase gradually with the advance of cutting.
(c) Cleavage fracture occurs.
(3) There is good agreement between the observed shear angle and the expected one based on the assumption that shear deformation occurs in the slip system {011}⟨111⟩ and {112}⟨111⟩.
(4) Cleavage fracture occurs with a small angle difference between the direction of the resultant cutting force and the direction of intersection of the cleavage plane {011} and the side plane of a workpiece.
(5) In the case of stable cutting, the shear stress in shear plane (τ) is related to the shear strain (γ) by the following equation. τ=13+39γ (kg/mm2).View full abstractDownload PDF (1097K) -
Mitsuo Chigasaki, Kô Soeno1975 Volume 39 Issue 8 Pages 817-825
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation in Fe-10 at%Ni-(1.5, 3, 4, 5, 6) at%Al and Fe-10 at%Ni-(1.5, 3, 4, 5) at%Be martensitic steels has been investigated by microscope observations and hardness measurements. Besides homogeneous precipitation, cellular precipitation is observed. It is also observed that cellular precipitation decreased with decreasing Al or Be content and the precipitation in the steels containing 1.5 at%Al or 1.5 at%Be proceeds in a homogeneous mode.
Effects of small amounts of additional elements on the cellular precipitation have been investigated. Cellular precipitation is markedly suppressed by small additions of Nb, Ti or Mo. Recrystallization behaviors of cold worked Fe-10 at%Ni martensitic steels containing small amounts of ternary additional elements have also been investigated. It is shown that the elements which raise the recrystallization temperature of the Fe-10 at%Ni steel have a tendency to suppress the cellular precipitation in the Fe-10 at%Ni martensitic steels containing 3 to 6 at%Al or 3 to 5 at%Be.View full abstractDownload PDF (1258K) -
Takashi Nishimura, Hiromichi Kawahara1975 Volume 39 Issue 8 Pages 825-831
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTitanium alloys containing beta stabilizing and eutectoid forming elements are known to exhibit embrittlement after thermal exposures up to the eutectoid temperature. This phenomenon in the commercial titanium alloy Ti-5Al-2Cr-1Fe was investigated by the room-temperature tensile test, impact test, electrical resistance measurement, light and electron microscopy and X-ray diffraction after thermal exposures in the temperature range of 300 to 500°C for various times up to 5000 hr under both stressed and unstressed conditions.
The results obtained are as follows:
(1) The embrittlement in this alloy is accelerated by raising the temperature of thermal exposure and by stressed conditions.
(2) Analysis of data of mechanical properties, electrical resistance, microstructure and X-ray diffraction defines the embrittlement is attributed to the intermetallic compound TiCr2 phase which forms during thermal exposure. The activation energy for thermal exposure reaction approximates that for diffusion of chromium in the beta phase.
(3) As the embrittlement is found to be closely related to the thermal exposure reaction, the time-temperature relationship for the embrittlement can be given by the following equation:
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (884K) -
Tohru Watanabe, Yoshimi Tanabe1975 Volume 39 Issue 8 Pages 831-836
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMorphorogy of Ni-B amorphous alloys prepared by a electroless deposition method with NaBH4 and its reproducible preparation conditions were investigated. Electroless deposited Ni consisted of the aggregate of microcrystals, but these microcrystal size decreased as the reducing agent concentration in the plating bath is increased. At the concentration of 400 mg/l or above, the morphorogy of the deposited Ni film was an amorphous state. The increase of the reducing agent concentration increases the concentration of boron in the deposited Ni film. When the boron concentration is lower than 11.4%, the deposited film was crystalline but in the case of the saturated concentration (11.4%), the structure became amorphous. It was revealed, therefore, that a high boron content in the deposited film was necessary to form amorphous films, and that the amorphous alloy could be prepared independent of depositing temperature, substrate materials and deposition time.View full abstractDownload PDF (736K) -
Kouzou Tsunoyama, Hideji Suzuki1975 Volume 39 Issue 8 Pages 836-840
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStrain aging of polycrystalline specimens of Fe-Mn-N alloy was investigated by measuring the change of electrical resistivity and the recovery of yield point. The strain aging takes place in two stages. In the first stage the concentration of solute nitrogen, measured by electrical resistivity, decreases while the yield point increases. Both changes are proportional to t2⁄3, where t is the aging time. In the second stage, the solute atoms continue to drain, the yield point is nearly independent of t. Stress relaxation and micro-strain measurements after aging reveal distinct differencence in the deformation process between these two stages. These measurements suggest that the average distance between pinning points in a screw dislocation increases during the aging. Of course the pinning force of each pinning point increases more rapidly than the distance between pinning points, so that the age hardening takes place.View full abstractDownload PDF (442K) -
Takashi Kuse, Teruji Makuuchi, Toshiharu Matsuki1975 Volume 39 Issue 8 Pages 841-847
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh temperature oxidation and sealability of Fe-29Ni-17Co alloy containing Ce, Al and Si, which is used for hard glass sealing, have been investigated by means of thermobalance, scanning electron micrograph and X-ray micro-analysis.
This alloy shows a good adherence between the oxide film and metal. As a result, the alloy shows good sealability. This can be attributed to the growth of the Si oxide layer between the oxide film and metal, and the internal oxidation of Al and Si.
Oxide film consists chiefly of α-Fe2O3, Fe3O4 and CoO·Fe2O3. At the initial stage of oxidation, the network of spinel type oxide builds up on the surface, the width of this oxide increases as oxidation proceeds. The activation energy for oxidation changes at about 900°C, amounting to 61.9 kcal/mol on the high temperature side and 28.7 kcal/mol on the low temperature side. Oxidation rate is lower for this alloy in comparision with the rate of an alloy to which Ce, Al and Si were not added.View full abstractDownload PDF (678K) -
Shiro Matsuda, Katsuhisa Sugimoto, Yoshinobu Sawada1975 Volume 39 Issue 8 Pages 848-856
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe optical constant for a “film-free” surface of 18-8 stainless steel was determined as \barn3=2.67−4.03i (at 5461 Å) by ellipsometric measurements in dehydrated methanol immediately after the “film-removing” treatment in a 0.5% bromine-methanol solution.
Using this optical constant of the “film-free” surface, the ellisometric parameters, Δ and Ψ, for the steel measured in 1M-Na2SO4 solutions of vavious pH under potentiostatic control were analyzed in order to obtain the optical constants and the thickness of the films formed in these conditions. The optical constants of passive and transpassive films were dependent on the pH of solutions used, and summarized as follows;
for the passive film as \barn2=2.5−0.5i (pH=6.45), \barn2=2.5−0.6i (pH=4.0), \barn2=2.0−0.2i (pH=2.0∼3.0), \barn2=2.0−0.1i (pH=0.0), and for the transpassive film as \barn2=3.0−0.6i (pH=6.45), \barn2=3.0−0.3i (pH=4.0), \barn2=3.0−0.4i (pH=3.0).
The difference in optical constants between the passive and the transpassive films could be attributed to the difference in chemical compositions of these films, which were analyzed by means of ESCA.
The thickness of the passive film was a function of the electrode potential and of the pH of solutions used. The growth rate of the film thickness with potential increased with increasing pH of the solutions, and the maximum thickness of the passive films formed in neutral solutions was larger than those of the films formed in acidic solutions.View full abstractDownload PDF (836K) -
Yutaka Nakayama, Taichiro Ito, Hiroshi Mabuchi, Yasunori Taruno1975 Volume 39 Issue 8 Pages 857-863
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSingle crystals of Cu-Si alloy oriented for single slip were subjected to tensile deformation. It was confirmed that the initial stage of easy glide (stage I) in crystals with small amounts of Si had very little hardening (stage IA) for a few per cent elongation. The extent of stage IA increased with decreasing temperature from 295 to 77°K and with increasing Si content from 1.5 to 2.4 at%. On the other hand, the density and distribution of dislocations in stage IA in Cu-1.5 at%Si crystals were studied by the etching method. The dislocation distribution was very inhomogeneous; the dislocation density was distinctly high along band-like slipped regions parallel to the trace of the primary glide plane. In slipped regions, the dislocation density was of the order of 107 cm−2, and dislocation multiplication was not detected in secondary slip systems. The deformation during stage IA was characterized by the growth of slipped regions in width and the formation of new slipped regions between old ones formed earlier. When the specimen surface was all covered with slipped regions, stage IA ended and followed by stage I hardening. The deformation in stage IA was apparently similar to “Lüders deformation” in single crystals of copper alloys with high concentrations of alloying elements. However, as the density and distribution of dislocations in stage IA are considerably different from those in Lüders deformation, stage IA is thought to be different from Lüders deformation.View full abstractDownload PDF (1253K) -
Takasi Takezawa, Toru Yokoyama1975 Volume 39 Issue 8 Pages 863-867
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThermal expansion of FeCo alloys in the bcc range have been measured. The volume changes due to the ordering of 30∼70 at%Co alloys decrease at the order-disorder transition temperature Tc, and the expansivities of these alloys decrease as the long-range order parameter increases. The mean expansivities of the ordered 25∼70 at%Co alloys are less than those of the disordered ones in the temperature range from 100 to 200°C. The volume change due to the ordering at room temperature decreases in 27.5∼33.3 at%Co and increases in 40∼70 at%Co.
The volume increase due to the ordering at room temperature of the 40∼70 at%Co alloys is more affected by the decrease of the expansivity than the contraction due to the ordering.View full abstractDownload PDF (448K) -
Hirotomo Tominaga, Shigetomo Ueda1975 Volume 39 Issue 8 Pages 867-871
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe aluminum concentration distribution in the diffusion coated layer changes during the high temperature oxidation of aluminum diffusion coated stainless steel. Thus, the aluminum concentration at the metal/oxide interface decreases progressively with continued interdiffusion, eventually rendering the surface protective oxide thermodynamically unstable. Aluminum diffusion coating only confers a limited protection against oxidation, even if it is proof against mechanical failure. In the present work, the oxidation resisting time or the time to breakaway, for which the interface aluminum concentration decreased to the critical concentration for the formation of protective oxide, was calculated approximately by applying Fick’s law to diffusion coating and oxidation. The calculated results were close to the experimental values measured through weight gain for oxidation.View full abstractDownload PDF (416K) -
Takeshi Mori, Hiroshi Fujita1975 Volume 39 Issue 8 Pages 872-880
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSlip deformation in single crystals of Cu-8 at%Al alloy has been examined by simple tension. The main results are summarized as follows: (1) The specimens oriented for a single slip system (specimen A) generally show the typical Lüders-type deformation. On the other hand, in the specimens oriented for a double slip system (specimen B), in which slip-bands appear in various regions all over the specimen in general, the deformation mode also changes to Lüders-type one when the specimen thickness decreases. (2) In specimen B, which does not show the Lüders-type deformation, new slip-bands are also formed in the undeformed regions between the old slip-bands. Lamellar structure of these individual slip-bands developes prominently compared with that in specimen A. Even in specimen A, the lamellar structure is well developed in thick specimens. These facts are closely related to the activation of secondary slip. (3) At the front region of Lüders-type deformation, the crystal rotation due to deformation results in the bending of the specimen. Slip-bands in these specimens are generated at the concave side, where the additional tensile stress is caused, and propagate to the convex side, where the additional compressive stress is caused. These slip-bands consist of a single or a few slip-lines with a large amount of shear strain at the concave side and an assembly of many slip-lines with a small amount of shear strain at the convex side. On the other hand, the slip-bands in specimen B consist of a dense assembly of the fine slip-lines. (4) Yield drop is caused by the Lüders-type deformation, and closely related to the bending stress at the deformation front.View full abstractDownload PDF (2202K) -
Measurements of Thermodynamic Quantities for Sn-Zn and In-Sb Alloys by Quantitative Thermal AnalysesKimio Itagaki, Akira Yazawa1975 Volume 39 Issue 8 Pages 880-887
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe measurements of thermodynamic quantities for tin-zinc and indium-antimony binary alloys were carried out by the quantitative thermal analyses in the cooling and the heating process. A water calorimeter and a double adiabatic walls calorimeter were used respectively for the cooling and the heating process.
In the experiments, the enthalpies of the alloy specimen are measured successively during cooling or heating the specimen, and so, for obtaining the precise data, it is necessary to keep the alloy phases in equilibrium state during the processes. Especially, the cooling velocity and the temperature distribution in the specimen give serious effects on the precision of the experiments in the cooling process. The influences of some factors such as the sample quantity, the thermal conductivity of the specimen and the heat exchange between the specimen and the water calorimeter were investigated quantitatively and the proper conditions for the experiments were suggested.
In the experiments by the heating process, the deviation from the phase equilibrium could be minimized by adjusting the heating rate and stirring the specimen, and the obtained results for the thermodynamic quantities agree well with the reliable published data.View full abstractDownload PDF (639K)
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