著者

A. Inoue A. Kato T. Zhang S. G. Kim T. Masumoto

出版者

The Japan Institute of Metals

雑誌

Materials Transactions, JIM (ISSN:09161821)

巻号頁・発行日

vol.32, no.7, pp.609-616, 1991 (Released:2007-06-01)

参考文献数

11

被引用文献数

489 509

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A low pressure casting of Mg–Cu–Y melts into copper molds was found to cause amorphous bulks in a cylindrical form. The maximum diameter of the amorphous cylinder (Dc) shows a significant compositional dependence and reaches a maximum value of 4.0 mm for Mg65Cu25Y10. The compositional dependence of the Dc is similar to that for the temperature span of the supercooled liquid region, ΔTx(=Tx−Tg). The similarity is presumably because the alloy with large ΔTx has a high resistance against the nucleation and growth of a crystalline phase resulting from the formation of a disordered structure with a more dense random packing and an optimum bonding states. The compressive proof stress at an elongation of 0.2% (σp) for the Mg80Cu10Y10 cylinder was 822 MPa at room temperature and the fracture occurred along the shear plane. The σp remains unchanged up to 350 K and then decreases significantly with increasing temperature, accompanied by the change in the deformation mode from inhomogeneous to homogeneous type. There is no appreciable difference in the features of mechanical strengths and deformation behavior between the bulk and ribbon samples, indicating the similarity of the disordered structure.

著者

Nobuyuki Nishiyama Akihisa Inoue

出版者

The Japan Institute of Metals

雑誌

Materials Transactions, JIM (ISSN:09161821)

巻号頁・発行日

vol.38, no.5, pp.464-472, 1997 (Released:2007-06-01)

参考文献数

34

被引用文献数

108 111

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A Pd40Cu30Ni10P20 alloy subjected to B2O3 flux treatment was found to have a low critical cooling rate (Rc) of 0.100 K/s for glass formation and a large sample thickness (tmax) of 72 mm by the water quenching process. The Rc and tmax exceed largely those (Rc=1.57 K/s, tmax=40 mm) for the Pd–Cu–Ni–P alloy without the flux treatment. It is concluded that the flux treatment causes a significant increase in the thermal stability of the supercooled liquid. The glass transition temperature (Tg) remains unchanged in the fluxed state, but the crystallization temperature (Tx) increases by 7 K, leading to the extension of the supercooled liquid region defined by ΔTx(=Tx−Tg) to 98 K which is larger than that (91 K) for the non-fluxed sample. The decrease in Rc and the increases in tmax and ΔTx for the fluxed sample are presumably due to the suppression of heterogeneous nucleation for crystallization resulting from the increase in the degree of cleanness of the molten alloy. Besides, the Pd–Cu–Ni–P amorphous alloy has lower Rc and melting temperature (Tm) and larger tmax, ΔTx and Tg⁄Tm values, as compared with those for Pd40Ni40P20 alloy. The larger glass-forming ability for the Pd–Cu–Ni–P alloy is presumably due to the increase in the degree of the satisfaction of the three empirical rules for the achievement of larger glass-forming ability resulting from the more systematic change in atomic size in the order Pd>>Cu>Ni>>P and the generation of Cu–Pd and Cu–P atomic pairs with negative heats of mixing. There is no appreciable difference in the Tg, Tx and crystallization behavior between the cast 72 mmφ amorphous ingot and melt-spun amorphous ribbon. The finding of the fluxed Pd40Cu30Ni10P20 alloy with the lower Rc and larger tmax values is promising for the future development of bulk amorphous alloys.

著者

TSUNEKAWA Shin KASUYA Atsuo NISHINA Yuichiro FUKUDA Tsuguo

出版者

社団法人 日本金属学会

雑誌

Materials transactions, JIM (ISSN:09161821)

巻号頁・発行日

vol.37, no.4, pp.650-654, 1996-04

参考文献数

14

被引用文献数

6

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LaNbO<SUB>4</SUB> crystals show three lineal structures associated with domain formation under high-resolution polarizing optical microscope. One has a width of the order of 10 microns and the others are in order of 1 micron wide. The former is a large scale multidomain structure formed by twinning deformation due to monoclinic spontaneous strains below phase transition temperature and the latters are a small scale multidomain structure comming from discommensuration due to incommensurate-commensurate phase transition. Spacings of these multidomain structures are discussed on basis of experimental results and theoretical consideration.

著者

Eiichiro Matsubara Shigeo Sato Muneyuki Imafuku Takahiro Nakamura Hisato Koshiba Akihisa Inoue Yoshio Waseda

出版者

The Japan Institute of Metals

雑誌

Materials Transactions, JIM (ISSN:09161821)

巻号頁・発行日

vol.41, no.11, pp.1379-1384, 2000 (Released:2007-06-01)

参考文献数

15

被引用文献数

13 14

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This paper has been retracted by the Editorial Committee with the first author’s agreement due to substantial overlap with the following paper previously received in another journal. Mater. Sci. Eng. A 312 (2001) 136-144 Structural study of Amorphous Fe70M10B20 (M=Zr, Nb and Cr) alloys by X-ray diffraction E. Matsubara, S. Sato, M. Imafuku, T. Nakamura, H. Koshiba, A. Inoue, Y. Waseda (Received on May 8, 2000) And thus, it shall not be regarded as an original paper. Although this paper was submitted to the Special Issue on Bulk Amorphous, Nano-Crystalline and Nano-Quasicrystalline Alloys by the first author without understanding the bylaws of Materials Transactions, JIM, it was not an appropriate deed. The first author acknowledges the substantial overlap and his apologies have been accepted accordingly. The notice has been issued to all the authors to pay more careful attention in submitting papers.