著者

吉田 浩一 大中 逸雄

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.61, no.4, pp.342-349, 1997 (Released:2008-04-04)

参考文献数

20

被引用文献数

2

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An algorithm has been developed for simulating the solidification in copper billet continuous casting based on the direct finite difference method by assuming a flow field in the melt. The simulation model considers the temperature dependent thermo-physical properties, convection heat transfer due to the movement of liquid and solid phases, latent heat of solidification and heat transfer among carbon and copper molds, billet and cooling water. The simulation results were compared with a measured sump shape, cooling curves and dendrite-arm-spacing (DAS). The sump shape was estimated from the solidification structure obtained by adding molten Sn during casting. An experimentally determined relationship between DAS and cooling rate was used in the estimation of the DAS distribution in the billet. The comparison between calculated and measured results showed a good agreement and it was found that neglecting the heat transfer into the casting direction results in a maximum error of 16.4%. It was also found that a more accurate estimation of the thickness of the solidified layer and temperature near meniscus requires more accurate information on the velocity field.

著者

國貞 雄治 坂口 紀史

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.9, pp.570-574, 2016 (Released:2016-08-25)

参考文献数

24

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We have investigated trapping effects of monoatomic vacancies Vmono and alloy atoms on hydrogen diffusion at Al(111) surfaces. We performed first-principles calculations based on density functional theory with generalized gradient approximation in order to obtain the hydrogen adsorption energies in the vicinity of monoatomic vacancies and alloy atoms in Al(111) subsurfaces. We considered Si, Cr, Mn, Fe, Cu, Ge, and Zn as alloy atoms. We substituted one Al atom with one monoatomic vacancy or alloy atom, which corresponds to Al0.95X0.05(111) (X=Si, Cr, Mn, Fe, Cu, Ge, Zn, Vmono) surfaces. We found that all of monoatomic vacancies and alloy atoms increase adsorption energies. We also clarified that hydrogen atoms make strong covalent bonds in Cr, Mn, Fe-alloyed Al(111) subsurfaces, while they make only weak ionic bonds in pure and Si, Cu, Ge, Zn-alloyed Al(111) subsurfaces.

著者

小川 由希子 安藤 大輔 須藤 祐司 小池 淳一

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.3, pp.171-175, 2016 (Released:2016-02-25)

参考文献数

25

被引用文献数

4 9

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Mg-20.5 at% Sc alloy with hcp (α)+bcc (β) two-phase alloy was investigated to understand the effects of aging treatment at 200℃ on microstructure, hardness and tensile properties. The Mg-Sc alloy ingot was prepared by induction melting in Ar atmosphere, and then hot rolled at 600℃ followed by cold rolling into a sheet. The rolled specimens were annealed at 600℃ to obtain α+β two-phase microstructure. Then, the annealed specimens were aged at 200℃ for various time. Vickers hardness of the α+β two-phase alloy drastically increased after a certain incubation time and then reached maximum hardness of 142.8 Hv. The incubation time of the Mg-20.5 at% Sc alloy with the α+β two-phase was longer than that of the same alloy with a β single-phase. Ultimate tensile strength (UTS) and elongation of the as-annealed specimen were 280 MPa and 28.2%, respectively. Meanwhile, the specimen aged at 200℃ for 14.4 ks showed a UTS of 357 MPa and an elongation of over 12%. The specimen aged for 18 ks showed a higher UTS of 465 MPa while keeping a better elongation of 6.9%. It was found that the age hardening of the Mg-Sc alloys were attributed to the precipitation of very fine α phase in β phase.

著者

Wang W. G. Matsugi K. Fukushima H. Sasaki G.

出版者

公益社団法人 日本金属学会

雑誌

MATERIALS TRANSACTIONS

巻号頁・発行日

vol.48, no.7, pp.1948-1954, 2007

被引用文献数

11

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AZ91D magnesium alloy reinforced with aluminum borate whisker (Al<SUB>18</SUB>B<SUB>4</SUB>O<SUB>33w</SUB>, denoted by ABO<SUB>w</SUB>) was fabricated by squeeze-casting. The heat treatment (T4) was carried out at 693 K in argon atmosphere for 48 and 96 hours, respectively, following water-quenched. The behaviors of interfacial reaction were studied in processes of fabrication and following heat treatment. Microstructures of interfacial reaction layers were investigated with transmission electron microscopy (TEM). Interfacial reaction layer in thickness of 5&ndash;10 nm was found in as-casted composite, and it was identified that the interfacial reaction layer was consisted of MgO. When the composite was heat-treated at 693 K for 48 hours, the surfaces of whiskers were covered with interfacial reaction layer completely and the thickness of interfacial reaction layer increased to about 20 nm. With increasing the time of heat treatment from 48 hours to 96 hours, the thickness of interfacial reaction layer on the surfaces of whiskers did not change obviously. The interfacial reaction layer was consisted of tiny MgO particles and a small quantity of MgB<SUB>2</SUB> particles. Although MgO particles played a good barrier to keep out of contacting between magnesium and whisker, the boundaries between MgO particles acted as a shortcut of magnesium atoms migration. Therefore magnesium could keep on reacting to whisker. The interfacial reaction could invade into the inner of whisker about 20 nm depth after the composite was heat-treated at 673 K for 96 hours. The surfaces of whiskers became wave-like because of interfacial reaction. An orientation relationship was found between MgO reaction layer and ABO<SUB>w</SUB>: (11\\bar1)<SUB>MgO</SUB>||(320)<SUB>ABOw</SUB> and [011]<SUB>MgO</SUB>||[001]<SUB>ABOw</SUB>. The surfaces of MgO particles were consisted of close-packed (111)<SUB>MgO</SUB> plane.

著者

宮崎 修集

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.35, no.2, pp.179-184, 1996-02-01 (Released:2011-08-11)

参考文献数

46

被引用文献数

2 3 9

著者

馬越 佑吉

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.51, no.5, pp.203-208, 2012 (Released:2012-12-27)

参考文献数

20

被引用文献数

1 1

著者

志賀 正幸

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.44, no.3, pp.233-241, 2005-03-20 (Released:2011-08-11)

参考文献数

5

著者

岩崎 重義

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.34, no.8, pp.995-1001, 1995-08-20 (Released:2011-08-11)

著者

徳永 良邦 山崎 一正

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.34, no.6, pp.699-704, 1995-06-20 (Released:2011-08-11)

参考文献数

28

被引用文献数

2 1

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.60, no.12, pp.769-772, 2021-12-01 (Released:2021-12-01)

参考文献数

8

被引用文献数

1

著者

森戸 春彦

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.59, no.5, pp.229, 2020-05-01 (Released:2020-05-01)

参考文献数

5

著者

佐和 康二 加藤 光郎 川瀬 昇

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.48, no.12, pp.621, 2009 (Released:2012-10-27)

著者

石井 和秀 石井 知洋 宇城 工 柳沼 寛 山下 英明

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.47, no.1, pp.45-47, 2008-01-01 (Released:2011-08-11)

参考文献数

4

被引用文献数

4 4

著者

齊藤 拓馬 原田 広史 横川 忠晴 大澤 真人 川岸 京子 鈴木 進補

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.86, no.9, pp.157-171, 2022-09-01 (Released:2022-08-25)

参考文献数

80

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Series of Ni-base single-crystal superalloys with superior thermal durability have been developed to improve thermal efficiency of gas turbine systems. Microstructural transition during creep so called “raft structure” formation enhances creep properties at lower stress and higher temperature condition. Furthermore, larger perfection degree of the raft structure contributes to better creep properties under the same creep condition. To control the perfection degree of the raft structure, magnitude of a lattice misfit and an elastic misfit between γ and γ′ phases should be controlled. In the current situation, the lattice misfit can be controlled by using alloy design program NIMS has developed. In this review, we focused on the role of the raft structure in alloy design. Observation results and predicted mechanisms about strengthening by the microstructural transition, in addition to the mechanism about microstructural transition itself during creep, were summarized and explained. Finally, under these recognitions mentioned above, our effort to establish a new alloy design approach to control the perfection degree of the raft structure by modifying the elastic misfit was introduced.

著者

小林 直弘 小山 元道 小林 憲司 北條 智彦 秋山 英二

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.85, no.2, pp.49-58, 2021-02-01 (Released:2021-01-25)

参考文献数

35

被引用文献数

6 5

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The grain size effects on the hydrogen embrittlement susceptibility of pure Ni and Ni-20Cr alloy were investigated. The hydrogen embrittlement susceptibility was evaluated by tensile testing under electrochemical hydrogen charging. Relative elongation, defined as the elongation under hydrogen charging divided by elongation in air, increased with increasing grain size in pure Ni (the grain size was in the range of 11-22 µm). In contrast, the relative elongation of Ni-20Cr alloy increased with decreasing grain size from 13 to 1.8 µm. Correspondingly, intergranular fracture was suppressed by grain coarsening in pure Ni and grain refinement in the Ni-20Cr alloy. In addition, the intergranular fracture surface in pure Ni showed curved slip lines, and in the Ni-20Cr alloy showed straight line marks. These fractographic features imply that the mechanisms of the hydrogen-assisted intergranular crack growth were different in pure Ni and Ni-20Cr alloy and this can be attributed to the difference in stacking fault energy.

著者

今出 政明 張 林 飯島 高志 福山 誠司 横川 清志

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.73, no.4, pp.245-250, 2009 (Released:2009-04-01)

参考文献数

22

被引用文献数

12 11

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The internal reversible hydrogen embrittlement (IRHE) of the thermally hydrogen-charged iron-based superalloy of SUH660 and austenitic stainless steels of SUS 304, 316, 316L, 316LN and 310S was investigated in the temperature range from 300K to 80 K. Hydrogen showed a marked effect on the tensile properties of SUH660 and SUS 304, a minimal effect on those of SUS316 and SUS316LN, and no effect on those of SUS 310S and 316L at room temperature. Although the IRHE of SUH660 decreased with decreasing temperature, those of SUS304, 316 and 316LN increased with decreasing temperature, reached a maximum at around 200 K, and decreased rapidly with decreasing temperature down to 80 K. It was observed that hydrogen caused transgranular fracture along the slip plane in the iron-based superalloy and brittle transgranular fracture along the strain-induced martensite lath in the austenitic stainless steels, respectively. It was suggested that IRHE of the SUH660 depended on the diffusion of hydrogen, and that IRHE of the austenitic stainless steels from 300 K to the maximum IRHE temperature depended on the transformation of strain-induced martensite and the behavior below the maximum IRHE temperature depended on the diffusion of hydrogen.

著者

田中 俊光 岩井 健治 杉本 明男 佐々木 敏彦 柴田 学

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.35, no.6, pp.725-727, 1996-06-20 (Released:2011-08-11)

参考文献数

4

被引用文献数

1 1

著者

田口 正美 馬場 司 神田 和紀

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.62, no.5, pp.481-487, 1998 (Released:2008-04-24)

参考文献数

14

被引用文献数

1 1

---

The thin film PbO2/PbO/Pb solid cells were produced by reactive sputtering and vacuum evaporation on glass substrates, and the discharge properties were investigated. A PbO2 layer was obtained by sputtering of the Pb target in oxygen plasma. PbO, which is an oxygen ion conductor, was deposited from β-PbO powder in a vacuum. The open-circuit voltage of the PbO2/PbO/Pb cell was in good agreement with the theoretical value based on the thermodynamic data, and the partial transformation of β-PbO to α-PbO in the electrolyte did not show any marked change in voltage. The close-circuit voltage, which could be measured by connecting with a 100 kΩ resistor, was deteriorated by doping of the Bi3+ ion to the electrolyte, PbO. On the other hand, the doping of the K+ ion inhibited the decrease in discharge voltage. Moreover, the charge-discharge cycling test revealed that the PbO2/PbO/Pb cell could be charged to behave as a storage battery and that the connection of the cells in series and in parallel supplied a higher electromotive force and a larger capacity.

著者

盧 鑫

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.59, no.9, pp.495-499, 2020-09-01 (Released:2020-09-01)

参考文献数

20

被引用文献数

1 2

著者

八木 俊介

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.85, no.10, pp.367-374, 2021-10-01 (Released:2021-09-25)

参考文献数

53

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Research and development of innovative energy storage and conversion devices are being actively pursued, such as supercapacitors, metal-air batteries, fuel cells, redox flow batteries, and rechargeable batteries using ions other than lithium ions as carrier ions. This review describes in detail the advantages and disadvantages of magnesium rechargeable batteries using magnesium ions as carrier ions. In addition, the key points of electrolyte development are explained. Furthermore, the progress and future challenges of electrolyte research, one of the most important elements of magnesium rechargeable batteries, are discussed in detail.