材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
32 巻 , 362 号
選択された号の論文の17件中1~17を表示しています
  • 遠藤 吉郎
    1983 年 32 巻 362 号 p. 1201-1207
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 玉利 昭一
    1983 年 32 巻 362 号 p. 1208-1212
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 大藪 権昭
    1983 年 32 巻 362 号 p. 1213-1217
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 高谷 泰之, 山川 宏二, 吉沢 四郎
    1983 年 32 巻 362 号 p. 1218-1222
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The corrosion of aluminum alloys in a saturated Ca(OH)2 solution containing NaCl has been studied through the measurements of weight loss and anodic polarization curves. The weight loss of aluminum alloy showed the following sequence: Al-Mg-Si>>Al-Zn>Al-Mg≅Al>Al-Mn>Al-Cu. It is concluded that the corrosion of aluminum alloys is controlled by the accumulation of corrosion products and its rate is proportional to the passivation current.
  • 御牧 拓郎, 藤本 堂之, 三浦 精
    1983 年 32 巻 362 号 p. 1223-1227
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Although there are many reports on stress corrosion cracking of α brass polycrystals in ammoniacal environment, few reports deal with α brass single crystals. So, in order to examine the effect of slip step on the initiation of stress corrosion cracking and the propagation mechanism of cracks, stress corrosion cracking tests were performed on Cu-27.8 at % Zn alloy single crystals (α brass) oriented to <321> and <211> in ammoniacal vapor at 298±1K.
    On α brass single crystals, stress corrosion cracking did not initiate at lower stress than the yield stress which is neccessary to move dislocations. The preformed slip steps did not influence the initiation of stress corrosion cracking, but the microcracks initiated from the slip steps caused by the active slip plane at higher stress than the yield stress.
    The orientation of the initiated cracks corresponded to {111} trace. Then the cracks propagated along {110} trace. On the specimen oriented to <211> where the conjugate slip system becomes active from the beginning of the tests, the cracks initiated at the area where dislocations were piled up by Lomer-Cottrell barrier.
  • 御牧 拓郎, 青木 英明, 藤本 堂之, 三浦 精
    1983 年 32 巻 362 号 p. 1228-1232
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    According to the previous investigations of stress corrosion cracking behavior on α/β brass being used as commercial brass, stress corrosion cracking initiates on β phase of brass. However, there are few reports on β brass single crystals.
    In order to clarify the stress corrosion cracking mechanism of β brass, stress corrosion cracking tests were performed on Cu-47.3 at % Zn alloy single crystals (β brass) oriented to <411> and <320> in ammoniacal vapor at 298±1K.
    In ammoniacal vapor, β brass single crystals were attacked and stress corrosion cracking was observed at a lower stress level than the yield stress. It is very different from the behavior of α brass single crystals.
    Corrosion groove was formed along the primary slip trace, that is {110} trace, and propagated along {211} trace at once. A microcrack initiated at the bottom of groove and propagated along {110} trace macroscopically, but the crack propagated in a zigzag way along {211} trace microscopically.
  • 内田 仁, 小寺沢 啓司, 隅田 守員, 山田 巌, 川辺 秀昭
    1983 年 32 巻 362 号 p. 1233-1237
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The susceptibility of subzero treated SUS 301 stainless steel to stress corrosion cracking (SCC) was studied in boiling 35% MgCl2 solution at 200MPa. The specimens were prepared by subzero cooling to 77K for 28.8ks after 0∼45% prestraining at 195K or 373K, and they were successively SCC-tested.
    The content of α'-martensite formed by subzero cooling was found to be maximum at about 5% prestrain at 373K. Above this prestrain, however, the mechanical stabilization of retained austenite occurred as a result of gradual decrease in α'-martensite content. On the other hand, the SCC susceptibility of the subzero treated specimens decreased with increasing α'-martensite content, which seems to be caused by promotion of general corrosion and thus prevention of crack initiation during SCC-tests. The transgranular fracture occurring along the {111} plane for the subzero treated specimens was characterized by the plate-like pattern. In this case, it seemed that ε-martensite contributed to the susceptible path for hydrogen cracking.
    Based on the above results, the role of thermally transformed martensite during SCC of metastable austenitic stainless steel was discussed.
  • 駒井 謙治郎, 箕島 弘二, 行待 博司
    1983 年 32 巻 362 号 p. 1238-1242
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The temperature dependence of static- and dynamic-SCC crack growth was examined on high-strength aluminum alloy sensitive to active path corrosion (APC) type SCC in 3.5% NaCl aqueous solution. Subcritical crack growth of static SCC in region II was thermally activated with an apparent activation energy of 78∼83kJ/mol, and the rate controlling step would be an anodic dissolution at grain boundaries. The threshold stress intensity factor KISCC, however, showed no dependence on temperature. Dynamic SCC at every temperature caused not only faster cracking in region II than that of static SCC, but also a decrease of the threshold value KDSCC from KISCC. The values of KDSCC were also independent of temperature. However, the thermally activated region II crack growth had two apparent activation energies. The apparent activation energy at low temperatures below approximately 318K was 21∼29kJ/mol, and this seemed to be related to alternation of two fracture mechanisms of anodic dissolution at grain boundaries and transgranular hydrogen embrittlement in a ligament zone. On the other hand, 84kJ/mol was obtained at high temperature, which indicated that anodic dissolution dominates over crack growth kinetics. The crack growth component by anodic dissolution [da/dt]AD and the one by hydrogen embrittlement [da/ dt]HE were obtained by applying a summation model taking accounts of fracture area fraction to dynamic SCC crack growth behavior. The results show that [da/dt]HE prevailes over [da/dt]AD at low temperatures, whilst at high temperatures the latter prevailes over the former.
  • 西田 俊彦, 冨田 弥寿夫, 西川 友三, 田中 謙次
    1983 年 32 巻 362 号 p. 1243-1247
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to investigate the mechanical behaviour of ceramic green bodies, the specimens of dried clay and alumina powder compacts were fractured by the three points bending technique. The values of fracture mechanics parameters, such as bending strength (σf), effective fracture energy (γeff), Young's modulus (Es), and fracture toughness (KIc), were determined for dried clay as 6.8MPa, 4.9J/m2, 1.6GPa, and 0.19MN/m3/2, respectively. On the other hand, the parameters for alumina powder compacts changed with the addition of a binding agent methyl cellulose (MC). Their σf and Weibull modulus (m) showed the maximum values at 1wt% MC, and with increasing MC content, γeff increased linearly but KIc hardly increased. The relations between the fracture mechanics parameters obtained and the behaviour of ceramic powder compacts during processing (cutting, drilling, and handling) were discussed in this report.
  • 門田 正胤, 加藤 健, 小倉 透, 速水 諒三
    1983 年 32 巻 362 号 p. 1248-1253
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Titanium carbide whiskers were prepared on a graphite substrate at 1250°C by CVD method using gases of TiCl4, CO and H2. The factors affecting growth of the whiskers were investigated. The presence of nucleating agents on the substrate showed a significant effect, and PtCl4 was most effective. By treating graphite substrates with various concentration of PtCl4 aq. solution, a desired dimension of whiskers could be prepared to some extent. X-ray diffraction revealed that the whiskers were titanium carbide with growth directions of <111> and <100>.
    Coating of the whiskers with Ni and Pt was performed by sputtering. Sputtered Ni on the whiskers revealed small droplets, whereas Pt was very smooth.
    The measurements of tensile strength showed the size effect and strength scatter similar to those reported on alumina whiskers. For the whiskers showing low strength, clear growth steps were found on the surface. The elastic moduli measured by 3-point bending also showed scatter and it may be explained by tapered shape of the whiskers. The effects of coating on strength and elastic modulus were not distinct.
  • 塩野 剛司, 大田 陸夫, 曽我 直弘
    1983 年 32 巻 362 号 p. 1254-1259
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Although the relation between stress intensity factor (KI) and crack velocity (v) in polycrystalline materials is to be affected by their microstructures such as grain size, porosity, grain boundary and so on, the dependence of subcritical crack growth on microstructures has rarely been investigated. Therefore, in this study, the KI-v relations for single-and poly-crystalline α-alumina were examined in order to obtain the information about such dependence and to study the stress corrosion mechanism in α-alumina.
    The specimens with a Chevron notch were fractured by the 4-points bending technique. The tests were carried out under a constant crosshead speed of 0.005mm/min. in air (20°C, 67%rh) and distilled water. The KI-v relations were obtained by the compliance analysis of load-deflection curves of stable fracture. Also the effective fracture energy (γeff) was measured by using the work-of-fracture technique.
    The values of γeff for two polycrystalline bodies were 35.30J/m2 and 15.74J/m2 in air, which were larger than that of single crystal (3.50J/m2). The positions of the curves in KI-v diagram for three materials corresponded to the magnitude of γeff. The difference in γeff between two polycrystalline bodies was explained on the basis of grain size. The n-values in v=AKIn measured in air and distilled water were nearly equal, and they were 65, 50, and 27 for single-, large grain and small grain poly-crystalline bodies, respectively. This difference may be attributable to the purity of alumina in the bodies. Stress corrosion was hardly observed in single crystal. For the polycrystalline bodies, the stress corrosion resistance was better in a higher purity alumina body. Consequently, it seems that the stress corrosion resistance of polycrystalline bodies depends largely on that of glassy phases in grainboundaries.
  • 逆井 基次, 浦島 和浩, 稲垣 道夫
    1983 年 32 巻 362 号 p. 1260-1263
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Based on the energy principle, a method for fracture mechanics applicable to elastic-plastic fracture of various kinds of ceramic materials was proposed. The elastic-plastic fracture energy associated with crack extension was separated quantitatively into the elastic energy release rate Gc for the cracks faces and the plastic energy dissipation φp. The importance of the plastic energy dissipation in the resistance for crack extension in the elastic-plastic fracture of an artificial isotropic graphite was elucidated by using the proposed energy method.
  • 後藤 隆泰, 花田 禎一, 曽我 直弘
    1983 年 32 巻 362 号 p. 1264-1268
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The elastic moduli of densified fused silica were determined by using the cubic resonance method capable of measuring the shear wave velocity and Poisson's ratio of small cubic specimens. The thermal expansivity and Vickers hardness were also determined, and an attempt was made to interpret the changes in these physical properties of fused silica due to densification on the basis of glass structure. The main results obtained were as follows:
    (1) The bulk modulus and Young's modulus increased about 60% and 40%, respectively, when fused silica was densified about 20%. The densified fused silica had higher bulk modulus (about 60%) and Young's modulus (about 20%) than α-quartz, even though both specimens had the same density.
    (2) The thermal expansion coefficient increased slightly with densification, but its value was considerably smaller than common crystals or glasses. Hardness increased about 60% with densification, which is comparable to the change in elastic moduli.
    (3) The increase in elastic moduli was not proportional to density but a sudden increase appeared at 2.4g/cm3 and 2.6g/cm3. This behavior may be interpreted in terms of the decrease in average bond length and the change in bonding angle of Si-O-Si.
  • 山田 修, 島田 昌彦, 小泉 光恵
    1983 年 32 巻 362 号 p. 1269-1273
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Fully dense AlN ceramics without additives were fabricated by high pressure hot-pressing, and temperature dependences of Vickers microhardness, fracture toughness and thermal conductivity were measured. The Vickers microhardness of AlN ceramics without additives was 1400kg/mm2 at room temperature and decreased gradually with increasing temperature up to 1200°C. The values of fracture toughness (KIc) were 3.0-4.0MN/m3/2 at room temperature and little temperature dependence of KIc was found up to 1200°C. The values of thermal conductivity were 40W/m·k at room temperature and 26W/m·k at 700°C.
  • 八尾 健, 神野 博
    1983 年 32 巻 362 号 p. 1274-1278
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The lattice constants and the molar fractions of Mn3+ ions in manganese aluminum oxides heat-treated under various oxygen partial pressures (Po2) were measured and the effects of the atmosphere of heat-treatment on the valence and the coordination state of manganese ions were investigated.
    Manganese carbonate and α-alumina were mixed in an equivalent ratio, and the mixture was heat-treated at 1400°C, 1300°C, or 1200°C under various Po2 from 2.1×10-1atm to 2.7×10-14atm. The lattice constants of the manganese aluminum oxides obtained were determined precisely. For two kinds of samples, the change of weight was measured at 1400°C, 1300°C, or 1200°C under various Po2, and then the molar fractions of Mn3+ ions in these samples were obtained as a function of Po2.
    The lattice constants and the molar fraction of Mn3+ ions changed similarly with Po2, i. e. they were almost constant at low Po2, increased abruptly at a certain Po2, and then increased gradually with increasing Po2. It is supposed that the substitution of Al3+ ions by Mn3+ ions taking place at high Po2 caused the increase of lattice constants. The abrupt increase in molar fraction of Mn3+ ions and the lattice constants is interpreted as follows: At low Po2 the distribution of cations in the spinel structure is normal as Mn2+ ions have the tetrahedral site preference. The increase of Po2 favors the formation of Mn3+ ions, which prefer the octahedral sites. Therefore, the structure becomes intermediate between the normal and the inverse, and the molar fraction of Mn3+ ions and the lattice constants increased abruptly.
  • 吉尾 哲夫, 三浦 嘉也, 小田 喜一, 高橋 克明
    1983 年 32 巻 362 号 p. 1279-1284
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Treatment of chromium-containing sludge by using glass has been known as a useful method for converting such sludge into a disposable glass-fixed body.
    In the present work, a systematic investigation was carried out in order to predict the appropriate conditions when applying this method to the treatment of practical sludge having various compositions.
    The mixtures of Cr(OH)3 and Ca(OH)2 as model sludge and bottle-glass and clay as fixing agent were heated at 1200 and 1400°C. The dissolution amount of chromium ions, the crystal phases deposited, and the appearance of the fixed body were examined for the obtained glass-fixed bodies. The results are summarized as follows:
    (1) The region of low dissolution of chromium ions (<1.5ppm) shows the similar tendency at both 1200 and 1400°C. This region expands to the Ca(OH)2 rich side with increasing clay.
    (2) The main crystal phases at 1200°C and 1400°C were uvarovite and Cr2O3, respectively.
    (3) The dissolution amount of chromium ions was closely related to the appearance of the fixed body. The samples with the appearance of glassy state or intermediate state between glassy and sintering states gave low dissolution amounts.
    (4) The addition of clay expanded the region of glassy state under the treatment condition at 1400°C for 2hr. The sample with the addition of 30wt% clay could be converted into a glassy fixed body up to the amount of 50wt% sludge (Cr(OH)3+Ca(OH)2).
  • 4. 弾塑性破壊力学とJ積分
    久保 司郎
    1983 年 32 巻 362 号 p. 1285-1291
    発行日: 1983/11/15
    公開日: 2009/06/03
    ジャーナル フリー
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