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Volume 50, Issue 10
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Chizuko Maeda, Yukio Inokuti, Yo Ito1986 Volume 50 Issue 10 Pages 869-873
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOrientation analyses of Kossel diffraction patterns of individual recrystallized grains in grain oriented silicon steel were performed by calculation without using Wulff net and were illustrated by the computer color mapping.
A (100) pole figure of bcc crystals can be calculated from data of (γ, ψ), by measurement of two nonequivalent 100 diffraction conics in the lattice space from a previously indexed chart. The crystallographic orientation of each grain can be expressed by color mapping using the normal and rolling directions (N.D. and R.D.) converted from (100) pole figures by calculative processing. The color mapping is produced by blending the angles of deviation from three vertexes with the primary colors, blue, red and green in the stereo-triangle. Moreover, the deviation angles of N.D. and R.D. of neighboring grains are calculated and illustrated by the width of grain boundary.View full abstractDownload PDF (617K) -
Yukio Inokuti, Chizuko Maeda, Yo Ito1986 Volume 50 Issue 10 Pages 874-878
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe crystallographic orientation of primarily recrystallized grains prior to the secondary recrystallization annealing in high induction grain oriented silicon steel was measured by use of the transmission Kossel technique. Computer color mappings of the results of crystallographic orientation for each grain were made using an image processing analyser.
It is evident that there are extremely large colonies of (110)[001] primarily recrystallized grains formed in the rolling direction in a clearly defined region with 100-200 μm width in the transverse direction and that the perfection of the [001] alignment of the colonized (110)[001] grains in this region is much better than that of the (110) crystallographic plane. The formation of the colonized (110)[001] grains and the perfection of the [001] alignment of these grains are more evident in the silicon steel containing a small amount of Mo than in that without Mo. These colonized (110)[001] grains are secondary nuclei and complete the preferential growth both by the coalescence of neighboring grains having a small angle grain boundary (of deviation less than π/18 rad) and by consuming other primary matrix grains with a large angle grain boundary (of deviation more than π/18 rad) at an incipient stage during the subsequent secondary recrystallization annealing.View full abstractDownload PDF (865K) -
Yukiteru Asayama1986 Volume 50 Issue 10 Pages 879-886
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the steels with composition of Fe-10Ni-3Cr-1.5Ti, the severe embrittlement occurred with the progress of aging regardless of presence of molybdenum. The embrittlement is not thought to be caused by grain boundary segregation of impurities giving rise to temper embrittlement in low alloy steels. The relationship between the embrittlement and precipitation behavior was studied in consideration of “activation energies” determined from Arrhenius plots. It is suggested that the embrittlement in these steels results from the formation of low temperature precipitates associated with the presence of titanium.
Also in the steel with composition of Fe-14Ni-2Mo-1.5Ti, the severe embrittlement occurred with the progress of aging as well as in the steels with composition of Fe-10Ni-3Cr-1.5Ti. When chromium is added to Fe-14Ni-2Mo-1.5Ti, the steel shows a good toughness even after the progress of aging. It was found that addition of chromium suppressed the formation of low temperature precipitates associated with the presence of titanium produced at an early stage of aging and promoted the formation of Laves phase produced with the progress of aging.
It is presumed that a close relationship exists between the precipitation behaviors and the notch toughness.View full abstractDownload PDF (1833K) -
Mutsuo Ohta, Teruto Kanadani, Masuo Yamada, Akira Sakakibara1986 Volume 50 Issue 10 Pages 887-892
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffect of the specimen thickness on the aging of Al-4 and 10 mass%Zn alloys was studied by measurements of the electrical resistance and the intensity of small-angle X-ray scattering (SAXS). When the quenching temperature (TQ) was high, the value of resistance attained when it substantially stopped to change in the aging process, was not influenced by the specimen thickness. In the case of low TQ, the resistance was higher for the thin specimen, caused by impoverishment of vacancies. The integrated intensity of SAXS depended neither on the thickness nor on TQ when TQ≥673 K, but it decreased with decreasing thickness and with decreasing TQ when TQ≤613 K. Both Guinier radius and Porod radius for the specimen of 0.1 mm thickness were smaller than those for the one of 0.2 mm thickness when TQ was low, but they became independent of thickness when TQ was higher than 673 K. The quenching temperature at which Guinier radius was maximum, was higher for the 0.1 mm thick specimen than that for the 0.2 mm thick one. These results have been discussed from the viewpoint of the diffusion of vacancies to the surface and their annihilation during aging.View full abstractDownload PDF (868K) -
Moritaka Hida, Eiichi Sukedai1986 Volume 50 Issue 10 Pages 893-899
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe age hardening of Ti-14 and 20 wt%Mo alloys at 623 K was investigated with their plate-like single crystal, bicrystal and polycrystal specimens in relation to crystal orientation and quenching strain induced by rapid cooling from 1223 K or 998 K for 20Mo and from 1223 K for 14Mo. The asquenched ω phase in single crystals showed higher hardness near the surface than that in the interior, when the specimen was mechanically abraded to a given depth. This phenomenon seemed to be influenced by solute oxygen and/or induced surface strain. The increase in age hardening in the interior, after a certain aging, kept up with that near the surface just under the contaminated layer (10-15 μm). The specimen with {110} surface hardened more quickly than that with {111} surface. The anisotropy of aging speed was verified with {320} and {211} surfaces of bicrystals (20Mo) for the quenching temperatures 1223 and 998 K. The effect of quenching temperature on age hardening was explained by the difference in the amount of quenched-in vacancies controlling the time period to the appearance of maximum hardness. After a long time aging, the interior of bicrystals showed a remarkable retardation of the age hardening.View full abstractDownload PDF (1091K) -
Takao Yakou, Tadashi Hasegawa1986 Volume 50 Issue 10 Pages 900-907
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThree kinds of material, Al single crystals (Al SX) and a non-directionally or directionally solidified Al-6 mass%Ni eutectic alloy containing Al3Ni particles or fibres in the Al matrix (Al3Ni particle/Al or Al3Ni fibre/Al, respectively), were deformed at room temperature in tension-compression tests, in order to make clear how and why the Bauschinger effect (B.E.) is influenced by the state of dispersion of hard Al3Ni second-phase.
The degree of B.E. at a given prestrain εp was found to be larger in the order of Al SX, Al3Ni particle/Al and Al3Ni fiber/Al. TEM observation showed that the tendency of tangled cell-wall formation in the Al matrix decreased (and as a result the density of isolated dislocations increased) in the same order, presumably due to an increasing difficulty of dynamic recovery during straining. On the assumption that the reverse strain after stress reversal is mainly caused by plastic deformation of the Al matrix, the higher back stresses (such as pile-up stresses) and the higher density of reversely-mobile dislocations, both of which may be associated with a uniform dislocation arrangement, can explain why the degree of B.E. increased in the observed order. Further, the degree of B.E. in all the materials examined was uniquely related to the so-called mean internal stress in the matrix ⟨σM⟩ only for a small εp (up to which the dislocation distribution was rather uniform); for a larger εp, the B.E. depended strongly on dislocation structures in the Al matrix even for a given ⟨σM⟩.View full abstractDownload PDF (1618K) -
Kenji Morinaga, Yoshio Ohta, Tsutomu Yanagase1986 Volume 50 Issue 10 Pages 907-914
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSElectrical conductivity (κ) of CaO-Al2O3-CaF2 melts has been measured by the four-electrodes method. Chemical analysis of fluorine has also been done by ion-chromatography. Iso-κ lines of the ternary system in this study were similar to those in previous studies. In the composition range with the Al2O3 content less than 15 mass%, however, κ was varied reversibly with the oxygen partial pressure (PO2) in the atmosphere, and was increased with increasing PO2. For example, κ of 10 mass% CaO-CaF2 melt under pure oxygen was about four times as large as that of the same melt under pure argon. The chemical composition of these melts was not changed with PO2 and the κ was varied linearly with PO21⁄4, and so this newly observed phenomenon may be caused by positive holes which were formed by the dissolution of oxygen into the melt. The presence of the positive holes was supported by the change in colour in samples.View full abstractDownload PDF (1073K) -
Masahiro Tosa, Kazuhiro Yoshihara, Kazuyoshi Nii1986 Volume 50 Issue 10 Pages 915-920
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAlumina films have been deposited on SUS 304 and SUS 321 stainless steels by the r.f. magnetron sputtering method. Titanium carbide precipitates on the surface of SUS 321 but not on the surface of SUS 304, when they are heated in a vacuum. In this report the effect of titanium carbide surface precipitation behavior on adhesion of deposited Alumina films has been observed.
Alumina coating stainless steels were heated at 1100 K and then cooled to room temperature in a vacuum. Alumina films on SUS 304 exfoliated but those on SUS 321 were stable. Thus, alumina films better adhered to SUS 321.
The result of AES and XPS showed that titanium carbide precipitated at the interface between alumina film and SUS 321 and also penetrated into alumina film. The strong adhesion of alumina film to SUS 321 is considered to be caused by the precipitated titanium carbide having a function as a bonding agent between alumina film and SUS 321.
In case of coating of other ceramics the precipitation of titanium carbide will also improve the adhesion.View full abstractDownload PDF (914K) -
Takeshi Kobayashi, Kunikazu Ide, Haruno Okochi1986 Volume 50 Issue 10 Pages 921-926
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn analytical method has been established for the determination of trace elements in very small samples by graphite-furnace atomic absorption spectrometry. Micrograms of samples of metal chips were dissolved in a small sized autoclave using a constant volume of mixture of acids as solvent. The trace amounts of As, Sn, Co, Ni, Cr and Sb in those sample solutions were determined by atomic absorption spectrometry. When the samples were dissolved in the autoclave, the volume of evaporated sample solution was monitored by measurement of the whole mass before and after the dissolution. Au was used as internal standard. As a result, it was known that the autoclave used was superior in maintenace of the solution volume, leading to high precision of the measurements. The analytical values of several standard samples (ca. 1 mg) used in this study were in good agreement with certified values of them. Therefore, it was found that even one milligram of them was able to sufficiently serve as standard reference materials. Detection limits (3σ) were 0.7, 0.8, 0.3, 0.2, 0.3, 0.3 and 0.3 ppm for As, Sn, Co, Ni, Cr, Sb and Au, respectively, when one milligram was used. The proposed method has a good accuracy and precision and is adequate to analysis of specimens of very small amount.View full abstractDownload PDF (894K) -
Takaharu Ichiryu, Itsuo Ohnaka, Hidehisa Tateoka, Isamu Yamauchi1986 Volume 50 Issue 10 Pages 927-934
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRapidly solidified wires of iron-silicon alloys of Si contents ranging between 4 and 12 mass% have been produced by the In-Rotating-Water-Spinning process. Addition of a small amount of cerium improved the spinning ability and produced uniform wires, which had silver-white luster and round cross sections and were 90 to 150 μm in diameter and 1 to 15 m in length. The oxygen content in the wires was not more than that in pre-alloyed ingots prepared in argon gas atmosphere. The wires containing Si less than 8 mass% had good ductility and were bent through 180 degree. The tensile strength of wire containing 6 mass%Si increased from 560 MPa to 950 MPa by cold-drawing of 26% reduction in area. Almost all wires had grains elongated in the spinning direction, and finer wires about 90 μm in diameter had a bamboo structure and showed high elongation without work hardening. It was suggested that the ductility was more affected by the grain size than by the ordered phase. The magnetic properties were comparable to those of melt-spun ribbons.View full abstractDownload PDF (2429K)
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