All issues
Volume 36, Issue 4
Displaying 1-21 of 21 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tetsu Oi, Kikuji Sato1972 Volume 36 Issue 4 Pages 287-290
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of arsenic and tin, which seem to be harmful to the toughness of steel, on the tempering process of highly pure Fe-1.0%C alloy were investigated. The contents of these elements were 0.5% or less for arsenic and 0.2% or less for tin. Resistivity measurements and transmission electron microscopy were carried out during the course of isochronal tempering.
The results are as follows:
(1) 0.5% arsenic retards the third stage, where cementite precipitates. It also has effects on suppressing the second stage where retained austenite decomposes, and the fourth stage where recovery and recrystallization occur.
(2) The fourth stage of tempering is suppressed as the content of tin increases.View full abstractDownload PDF (1068K) -
Tetsu Oi, Ryukiti Hasiguti1972 Volume 36 Issue 4 Pages 291-297
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWhen Fe-1.0%C-0.5%As alloy containing fine spheroidized cementite is quench-aged in the range of the alpha phase, anomalous precipitation is found in the neighborhood of 500°C. In order to clarify the origin of this phenomenon, measurements of electrical resistivity and internal friction, and direct observation with electron microscope were carried out.
The experimental results obtained are as follows:
(1) The anomalous precipitation seems to be the process for the solute carbon atoms to precipitate onto fine spheroidized cementites which have been formed previously.
(2) Free carbon atoms exist after quenching even in the alloy in which the anomalous precipitation occurs. These atoms precipitate with a normal two-stage precipitation process at 150°∼300°C. The above experimental results may be most plausibly explained by the following model:
(3) The As-C complex exists in the alpha solid solution of Fe-C-As alloy. The energy for the formation or decomposition of this complex is larger than the energy for the migration of carbon atoms in alpha iron. When the complex decomposes at about 500°C to bring supersaturation of carbon, it precipitates onto fine spheroidized cementites which have been formed previously. This process seems to correspond to the anomalous precipitation.View full abstractDownload PDF (2439K) -
Hisafuji Watanabe, Norio Kono, Mineo Gonda1972 Volume 36 Issue 4 Pages 297-305
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe phase diagram of the Cu-Zn-Mn system (mainly in the range of the Cu-Zn side) has been studied by means of inverse rate and differential thermal analysis, thermal dilatation and electrical resistance measurements, X-ray diffraction and microscopic examination. The ternary diagrams obtained are shown this paper.
(1) Seven non-variant reactions observed in this system are as follows:
(This article is not displayable. Please see full text pdf.)
(2) The T phase is a new ternary compound having a cubic structure with a lattice parameter of 6.979 Å.
(3) Mn affects appreciably on the β-β′ order-disorder transformation; i.e. the transformation temperature drops from 466°C in a binary Cu-48.7%Zn alloy to 402°C at the maximum solubility point of Mn in a ternary β′ solid solution.View full abstractDownload PDF (2483K) -
Takao Kusakabe, Shosuke Imoto1972 Volume 36 Issue 4 Pages 305-309
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThN powder, prepared by the reaction of metallic thorium with nitrogen and subsequently by the decomposion of the formed Th3N4, was intimately mixed with Th and ThO2 in various ratios.
\ oindentThese mixtures compacted in a disc form were heated at 1600°C for 17 hr or 1800°C for 5 hr in vacuum. Ceramographic, X-ray and chemical analysis of the samples showed a limited oxygen dissolution in ThN under these conditions. The main results thus obtained are as follows:
(1) The composition of the resulting ThN phase with maximum solubility of oxygen is ThN0.79O0.19 at 1600°C and ThN0.71O0.30 at 1800°C. The ThN phase seems to dissolve oxygen along the line from ThN to hypothetical (ThO).
(2) The lattice parameters of ThN0.79O0.19 and ThN0.71O0.30 respectively decrease to 5.157±0.001 Å and 5.155±0.001 Å from that of original ThN (5.158∼5.159 Å).View full abstractDownload PDF (1514K) -
Hiroshi Yamamoto1972 Volume 36 Issue 4 Pages 310-315
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFilaments of incandescent lamps are recrystallized and become brittle when lightened. It is necessary that the brittleness of the filaments has to be decreased in order to improve and stabilize the performance of lamps. In this investigation, the effect of the annealing in the drawing process on the recrystallization of wires was examined to establish the conditions for producing ductile filaments.
Samples used in this investigation were 2 kinds of tungsten wires doped with K, Si and Al. One was drawn to diameters of 0.055 to 0.207 mm without process-annealing. The other was drawn to a final diameter of 0.089 mm by changing the process-annealing. Tensile strength and structure changes of these samples, after recrystallization were investigated.
The experiments revealed that the drawing with a proper process-annealing gave fairly high tensile strength and recrystallization temperature to the drawn wires. The proper process-annealing is the heat treatment which is done twice in the process to reduce the tensile strength of the as-drawn wires by about 10 percent each time. Furthermore, it was shown that the wires with a fairly high recrystallization temperature became rather ductile after recrystallization.
The filaments made from the wires that had been treated under various conditions of process-annealing were subjected to tensile test after heating for recrystallization at higher temperature than the usual lightening temperature of the filaments, and the above-mentioned conclusion was confirmed to be valid.View full abstractDownload PDF (1785K) -
Masataka Sugiyama, Akira Sato1972 Volume 36 Issue 4 Pages 316-321
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn experimental work of di-directional solidification of pure aluminium and Al-Cu alloy ingots was carried out and their structures were investigated. Double-oriented ingots were obtained and their growth mechanism could be explained on the theory of preferred growth of dendrites whose growth direction ⟨100⟩ was perpendicular to the surfaces of two chills.View full abstractDownload PDF (2098K) -
Mutsuo Ohta, Fumio Hashimoto1972 Volume 36 Issue 4 Pages 321-328
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAl-rich Al-Zn alloys were studied mainly by measurement of electrical resistivity. The results may be summarized as follows: (1) The resistivity ρ0 immediately after quenching from various temperatures depends upon quenching temperatures TQ, and is smallest when quenched from about 250°C. (2) Large values of ρ0 which were obtained when TQ was higher than 250°C may be due to G.P.zones formed during quenching. (3) Large values of ρ0 which were obtained when TQ was lower than 250°C may be due to clusters which exist at quenching temperature and are frozen in by quenching. (4) Maximum resistivity ρM during isothermal ageing depends upon the quenching temperatures. For instance, in the case of ageing of Al-4.4 at%Zn alloy at 40°C, ρM are constant when TQ are in the range of 370°∼300°C. When TQ is higher than 400°C, ρM increases as TQ raises. When TQ is lower than 270°C, ρM decreases. (5) It is considered that larger values of ρM are observed when the number of G.P.zones formed during quenching is larger than the number of G.P.zones which are usually formed at that ageing temperature. Smaller values of ρM which were observed when TQ was lower than 270°C might be considered to show that the number of G.P.zones was decreased by clusters which were frozen in by quenching. (6) Metastable values of resistivity ρE which were obtained after resistivity maximum ρM depend upon both the number of G.P.zones formed during cooling and the concentration of vacancies. (7) Resistivity reaches a metastable value ρE′ in a short time when annealed at temperatures higher than the solvus temperature for G.P.zones and lower than the solvus temperature of the phase diagram. ρE′ depends upon annealing temperature TA, and independent of TQ. The values of ρE′ are on the extrapolated part of the ρ0−TQ curve. (8) The state corresponding to ρE′ might be a solid solution which contains clusters, and these clusters might be quite different from G.P.zones.View full abstractDownload PDF (2519K) -
Yoshitsugu Tomokiyo, Kunio Kaku, Tetsuo Eguchi1972 Volume 36 Issue 4 Pages 329-335
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSExtended dislocation nodes in αCu-Al solid solution were observed by a transmission electron microscope, and stacking fault energies (SFE) were determined. The specimens were annealed at 700°C after deformation to eliminate the effect of the solute impedance force pinning partial dislocation. Firstly, the variation in SFE with composition was measured and compared with Howie and Swann’s data. It appears that differences between their values and ours are due to the solute impedance stress. The SFE in pure copper was also estimated as 46.4±2.7 erg/cm2 using Liu and Gallagher’s relation. Secondly, the experiments were performed on the samples quenched from different temperatures to study the effect of short range order (SRO) on the SFE in Cu-15.9 at%Al. The SFE varies with quenching temperature, and the results show good correspondence with those of electrical resistivity, hardness and specific heat measurements. The variation in SFE with quenching temperature might be due to SRO rather than quenching stresses. The experiments suggest that SRO is not only responsible for the frictional effects as suggested by many workers, but also it might affect the true SFE.View full abstractDownload PDF (2571K) -
Yoshio Baba1972 Volume 36 Issue 4 Pages 335-341
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of 0.1 at%Cr, Zr, Fe, V, Ag, Be, Cd, In, Si, Ge, Sn and 0.01∼0.5 at%Cu on aging characteristics of an Al-9 at%Mg alloy have been studied by measurements of electrical resistivity and hardness and electron microscope observations.
The rate of clustering in Al-9 at%Mg alloy is remarkably decreased by the addition of more than 0.03 at%Cu. In the Cu-bearing alloys two kinds of cluster exist: the one is composed of Mg and Al atoms, and the other includes Cu atoms. The latter exists even above 100°C, in which the former is easily dissolved.
Transition elements such as Cr, Zr, Fe and V retard slightly the clustering, but accelerate precipitation at higher temperatures.
The effects of Ag, Be, Cd and In on aging kinetics are also similar to the case of those transition elements, except that these elements prevent the formation of precipitate-free zones and produce a finer dispersion of precipitates.
It seems that Si, Ge and Sn do not have the trace-element effect on the clustering and the precipitation in Al-9 at%Mg alloy.View full abstractDownload PDF (2209K) -
Yoshio Baba1972 Volume 36 Issue 4 Pages 341-346
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCorrosion cracking or season cracking occurs in the Al-Mg base alloys containing more than 5%Mg when exposed to tensile stress and a certain environment. An extensive study was undertaken to develope an aluminum alloy resistant to stress corrosion cracking. The effect of additions of 0.3%Cu and 0.2%Zr in Al-6∼9%Mg alloys on stress corrosion cracking has been investigated in 3.5%NaCl solution at room temperature under conditions of constant load and constant deflection.
The lowest stress causing corrosion cracking i.e. “threshold stress” is less than 3 kg/mm2 (corresponds to 23% of the 0.2% proof stress) for Al-8%Mg alloy quenched from 400°C and aged at 130°C for 7 days. Small additions of Cu, Zr and especially both elements improve the resistance to stress corrosion cracking of Al-Mg alloys. For Al-8%Mg-0.3%Cu-0.2%Zr alloy the “threshold stress” is 10 kg/mm and it is increased up to 15 kg/mm2 (corresponds to 83% of the 0.2% proof stress) when the alloy was air-cooled from the solution temperature.
Mechanisms of these effects are discussed on the basis of the direct observation of precipitates in grain boundaries and the measurements of electrical resistivity.View full abstractDownload PDF (1864K) -
Shitoshi Ohtani, Minoru Nishigaki1972 Volume 36 Issue 4 Pages 346-351
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe aim of the present work is to obtain a detailed knowledge of aging properties of Ti-Mo base beta alloys. Effects of solution-treatment, normal aging, two-step aging and isothermal transformation on the tensile properties, in connection with the microstructures, of three beta alloys were investigated.
Though aluminum suppressed precipitation of the omega phase, the embrittlement due to the alpha phase which was hardened by aluminum was remarkable in the Al-bearing alloy, Ti-12Mo-5Zr-3Al, in which the alpha phase precipitated in abundance. Ti-15Mo-5Zr-3Al showed a high strength of 143 kg/mm2 even after aging at a rather high temperature, 550°C, because aluminum strengthened the alpha. The optimum aging temperature range for the Al-free alloy, Ti-15Mo-5Zr, was narrow, in which balanced tensile properties with a ultimate tensile strength of 140 kg/mm2 and an elongation of 11% were obtained.
The alpha which precipitated primarily at grain boundaries after isothermal transformation was not effective for strengthening. There was no fundamental differences between normal and two-step aging in this study.
It is attributed to the recrystallization of beta grains that the precipitation site of the alpha phase during aging was affected by the preceding solution treatment. The Ti-15Mo-5Zr solution-treated at the temperature just below the beta-transus, consisted of the recrystallized and non-recrystallized grains, and the alpha phase which was not hardened by aluminum precipitated preferentially on dislocations in the latter grains. In the alloy solution-treated at a temperature considerably higher the beta transus, the alpha phase precipitated at grain boundaries. Ductility of the former alloy was much higher than that of the latter.View full abstractDownload PDF (1810K) -
Katsumi Muramatsu, Yoshinori Fujimura1972 Volume 36 Issue 4 Pages 352-357
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs has previously been reported on the lower bainite transformation, the effects of austenitizing temperature and time (longer than 60 min) on the upper bainite transformation (at 380°C) and the isothermal pearlite transformation (at 675°C) are investigated for a commercial eutectoid carbon steel heat treated at 1200°C for 20 min like those on the lower bainite transformation which were reported earlier. The principal findings are as follows.
(1) The amount of bainite formed during a certain transformation period increases to a maximum with increasing time and then starts to decrease. On the other hand, the amount of pearlite formed decreases to a minimum as the time increases, after which it increases to a maximum and again decreases.
(2) The higher the austenitizing temperature the shorter is the time to reach the maximum, and the lower the temperature the higher is the maximum in both bainite and pearite transformations. Besides, the higher the temperature the shorter is the time to reach the minimum pearlite formation, and the lower the temperature the higher is the minimum.
(3) Bainite or pearlite starts to nucleate at grain boundaries in the case of a short austenitizing time. However, this tendency of nucleation becomes a little weaker as the time increases and the nucleation also starts inside the grains. Furthermore, in the case of a long austenitizing time, bainite plates and pearlite nodules at grain boundaries or inside the grains are fine compared to those at grain boundaries in the case of a short austenitizing time.
(4) Nucleation of bainite or pearlite inside the grains is caused by the nuclear action by AlN. The nuclear action by AlN seems to be stronger in the bainite tranformation than that in the isothermal pearlite transformation.
(5) The value of activation energy obtained by assuming that a process to show the maximum amount of transformation is associated with that for thermal activation can be taken as 33.8 kcal/mol in all the upper bainite, lower bainite and pearlite transformations.View full abstractDownload PDF (2546K) -
Kazuyoshi Kamachi, Hideo Komeya, Shozo Ohbayashi1972 Volume 36 Issue 4 Pages 357-362
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor the purpose of studying the process to reach fracture in stress corrosion testing, X-ray diffraction patterns were analyzed and lattice faults were observed by transmission electron microscopy for the specimens during and after stress corrosion testing. From these experimental results, the half width ratio, the stored energy and the dislocation density were calculated. Then, the relation between the half width ratio and the dislocation density and the relation between the half width ratio and the life time were plotted. Both the half width ratio and the djslocation density against the logarithmic fracture time ratio were presented by one broken straight line. In addition, the stored energy was calculated from the analytical results of X-ray line profiles. The stored energy increased with the testing time and indicated the same value at the fracture time for the same kind of stainless steel.
It was also made clear that the relation between the stored energy and the dislocation density can be presented by a straight line, and that the stored energy arises from the lattice strain around the dislocation. Furthermore, we proposed a mechanism of stress corrosion cracking based upon the electron mcroscopic observation of the initial states of crack formation.View full abstractDownload PDF (1804K) -
Hisashi Suzuki, Motohiro Kanno1972 Volume 36 Issue 4 Pages 363-368
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation processes of a Cu-Zr-Cr ternary alloy have been investigated by means of specific heat and electric resistance measurements, comparing with those of Cu-Zr and Cu-Cr binary alloys. Specimens were solution-treated at 950°C and quenched into iced water. Subsequently they were aged or cold-rolled about 83% and then aged under various conditions. In this study, the precipitation processes during aging at temperatures elevated at a constant rate of 2°C/min were examined in detail. The results obtained were as follows: (1) In the as-quenched specimen, Cr precipitate appeared first at about 440°C and then Cu3Zr precipitate occurred separately at about 520°C. The former temperature was about 15°C higher than that of Cu-Cr alloy. In the worked specimen, the order of precipitation was reversed, that is, Cu3Zr and Cr appeared at about 370°C and 425°C, respectively. (2) The two sorts of precipitation temperature observed in each case of the ternary alloy agreed well with that of each binary alloy, with the exception of the above-mentioned temperature of Cr precipitates. (3) It was shown that the above results could satisfactorily be explained by the precipitation diagram (the T-T-T diagram) of the ternary alloy which was established qualitatively as consisting of four curves (two curves corresponding to homogeneous and heterogeneous precipitations of Cr and the other two curves of Cu3Zr). The property changes during isothermal aging can also be accounted for by using this diagram.View full abstractDownload PDF (1898K) -
Yasunori Tanji, Hiroshi Moriya, Yûki Shirakawa, Osamu Tamate1972 Volume 36 Issue 4 Pages 368-373
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relations among specimen dimensions, Young’s modulus E, and shear modulus G of rectangular and cylindrical bars have been evaluated experimentally for the various modes in vibration.
Correction coefficients Ti (i=fundamental, secondary and third vibrational modes) of E to the shape effect were obtained experimentally. The experimental values for Ti coincide very well with the theoretical values calculated by Teft. On the contrary to the case of the evaluation of E, the experimental values of G increase with shortening length of the specimens. The correction coefficient in the secondary vibrational mode of G, T2′, was obtained as a function of the cross section over length. Corrected values of E and G of soft steel are 2.110 T dyne/cm2 and 0.810 T dyne/cm2, respectively, and compressibility κ and Poisson’s ratio μ calculated from the corrected values G and E are 0.59 p cm2/dyne and 0.29, respectively.View full abstractDownload PDF (956K) -
Fukuji Inoko, Koichi Akizono, Genjiro Mima1972 Volume 36 Issue 4 Pages 373-379
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNon-isoaxial bicrystal specimens with various tilt boundaries and “pseudo-bicrystal” ones which consist of two component single crystals and have no compatibility were prepared.
From the relations between the tilt angle and the difference in flow stress between the bicrystal σBi and the pseudo-bicrystal σA+B, the effects of various tilt boundaries on the tensile deformation of the bicrystals were examined.
In a large number of the bicrystals with the tilt boundaries of less than 30° tilt angles, σBi−σA+B<0 were obtained at least near 2×10−3 strain. It is shown that there are two kinds of boundaries; one prevents the deformation of the bicrystal and the other promotes it.
Generally, the work-hardening rate of the bicystal was larger than that of the pseudo-bicrystal.View full abstractDownload PDF (2055K) -
Fukuji Inoko, Koichi Akizono, Genjiro Mima1972 Volume 36 Issue 4 Pages 380-384
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNon-isoaxial bicrystal specimens with various twist boundaries and “pseudo-bicrystal” ones which consist of two component single crystals and have no compatibility were prepared. From the relations between the twist angle and the difference in flow stress between the bicrystal σBi and the pseudo-bicrystal σA+B, the effects of various twist boundaries on the tensile deformation of the bicrystals were examined.
The results were similar to those of the bicrystals with the tilt boundaries i.e. in a large number of the bicrystals with the twist boundaries of less than 30° twist angles, σBi−σA+B<0 were obtained at least near 2×10−3 strain. The work-hardening rate of the bicrystal was larger than that of the pseudo-bicrystal.
As the new major factors of the effects of grain boundaries on the plastic deformation, the grain boundary structure itself and their relative orientation with the direction of applied stress and the slip vectors should be added.View full abstractDownload PDF (1023K) -
Kunio Shiobara, Susumu Morioka1972 Volume 36 Issue 4 Pages 385-392
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to understand the electrochemical mechanism of pitting and crevice corrosion of 18Cr-8Ni stainless steel, the electrochemical behaviour of 18Cr-8Ni stainless steel on the open surface and that in the crevice were studied in neutral sodium-chloride solution by means of a potentiostatic technique, preventing the crevice corrosion under insulation coating by prepassivation of the specimen. The presence of the pit-initiation potential, critical pitting potential and crevice corrosion potential was made clear. The results obtained may be summarized as follows. (1) Both the pit-initiation potential and the crevice corrosion potential of 18Cr-8Ni stainless steel in 0.1 M NaCl solution at 25°C were estimated at ca. +0.30 V (Eh), and the critical pitting potential at +0.70 V (Eh). (2) In the potential region between the pit-initiation potential and the critical pitting potential, a frequent oscillation of current was observed on account of the pit-initiation and repassivation, which was not affected by the dissolved oxygen concentration and the stirring of the solution. (3) The pit-initiation potential and the crevice corrosion potential depended upon the potential sweep rate and were not good in reproducibility, whereas the critical pitting potential was almost independent of the potential sweep rate and in a good reproducibility. (4) Increasing the NaCl concentration causes the pit-initiation potential, the critical pitting potential and the crevice corrosion potential to shift to a more negative potential. (5) The protection potentials of pitting and crevice corrosion were estimated at +0.3 and +0.03 V (Eh), respectively.View full abstractDownload PDF (1368K) -
Shozo Yoshioka, Yutaka Nakayama, Taichiro Ito, Hiroshi Mabuchi1972 Volume 36 Issue 4 Pages 393-397
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCu-Si single crystals containing 1.5, 2.4, 3.5 and 5.0 at%Si were investigated by tensile tests in the temperature range from −196° to 750°C and the strain rate range from 4.2×10−5 to 4.2×10−2 sec−1.
The results obtained are summarized as follows:
(1) At low temperatures from −196°C to room temperature, the yielding behaviour and stress-strain curves of Cu-Si single crystals is strongly dependent on the solute content. In Cu-Si single crystals containing more than 3.5 at%Si, stage I deformation occurs by Lüders band propagation.
(2) The discontinuous flows (Portevin-LeChatelier effects) are observed in the stress-strain curves at temperatures from about 70° to 550°C. While at high temperatures above 550°C, the high temperature yielding phenomenon are observed in Cu-3.5 and 5.0 at%Si single crystals.
(3) The temperature dependence of the critical resolved shear stress are found to be inverse in the temperature range from 300° to 550°C.
(4) In order to determine the characteristics of the high temperature yielding phenomenon, Cu-3.5 and 5.0 at%Si single crystals were deformed in the temperature range from 610° to 718°C and the strain rate range from 4.2×10−5 to 4.2×10−3 sec−1. The temperature and strain rate dependence of the yield stress can be determined by the equation of \dotε=Aτnexp[−U0⁄kT]. In Cu-3.5 at%Si, n=4.5 and in Cu-5.0 at%Si, n=3.7 and U0 are both nearly 2 eV.View full abstractDownload PDF (705K) -
K\={o}z\={o} Nakazawa, S\={o}kichi Umekawa1972 Volume 36 Issue 4 Pages 398-402
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe fracture behavior of 18-8 stainless steel fibers which were embedded in the Sn-Pb eutectic alloy matrix was studied. The progressive failures of fibers during the tensile test of the composite were detected by an acoustic technique. The following results were obtained.
(1) As the spacing of fibers in composite gets closer, a larger amount of strain of a fiber is localized in a small region which is located near the first fracture site of a neighboring fiber. Thus, the total elongation of the composite is relatively small due to a localized deformation. Contrary to this, for the larger spacing of fibers, deformation of the composite is uniform because fracture in many of the fibers occurs independently. This results in an increase in total elongation. Slip of the matrix arising from the break-down of a fiber develops at a domain which forms an angle of about 45° with the tensile axis.
(2) Only a single notch of a fiber in a 13 vol% fibers specimen has a considerable effect on the tensile strength of the composite, which is weakened remarkably compared with the composite with the same amount of flawless fibers. This effect was presumably caused by the same failure mechanism of fibers as in (1).
(3) The fracture strain of fibers in the matrix increases nearly two times greater than that of the isolated fiber.View full abstractDownload PDF (1132K) -
1972 Volume 36 Issue 4 Pages 402
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:Surface Films of Copper Alloys is 3%NaCl Aqueous Solution Right:Surface Films of Copper Alloys in 3%NaCl Aqueous SolutionView full abstractDownload PDF (21K)
- |<
- <
- 1
- >
- >|