JaLCDOI 10.18926/15818
フルテキストURL Mem_Sch_Eng_OU_20_2_21.pdf
著者 Yamada, Masuo| Ohta, Mutsuo| 榊原 精|
抄録 A series of small-angle X-ray scattering photographs with monochromated and point focussed copper Ka(1) radiation was taken of a single crystal of an Al-4mass % Cu alloy at the as-quenched state from 823K and at successive stages of ageing at 313K. The crystal was so oriented that the incident direction of the radiation was along [001] axis, and was cooled with liquid nitrogen during the exposure. The pattern of the as-quenched state was homogeneous, but each of the patterns of the aged states consisted of streaks along [100] and [010] directions and a quasi-ring around the trace of the incident beam on the film (even at the shortest ageing time. l6sec). The most intense regions were found in [100], [010] , [100] and [010] directions on the ring. With the progress of the ageing the streaks and the ring became more intense and narrower. The results can be interpreted from points of view of the formation of the GP zones parallel to {100} planes ab initio, the effect of the inter-particle interference on scattering of X-rays, and the growth of the GP zones with the ageing. Guinier radius of the GP zones at each stage can be obtained from intensity change along [110], and the values are reasonably consistent with those obtained from the cross section of the streak. The presence of multi-layer zones, besides the one-layer ones, is suggested from the humps found on several intensity curves along [100] at later stages.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1986-02-28
20巻
2号
開始ページ 21
終了ページ 33
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307538
JaLCDOI 10.18926/15808
フルテキストURL Mem_Sch_Eng_OU_20_1_35.pdf
著者 Yamada, Masuo| 榊原 精| Ohta, Mutsuo|
抄録 Photographic method for measurement of small-angl X-ray scattering (SAXS) is improved. Intense pointfocussing incident beam is obtained by using doubly bent crystal monochromator made of aluminium single crystal. Microphotometry and the subsequent calculation to obtain profiles, Guinier and Porod radii, integrated intensities, and so on are facilitated by using microcomputer. Integrated SAXS intensities measured from an Al-Zn alloy which has been treated under the same heat treatment conditions are coincident with one another with probable errors less than ±6 % . Ratio of the integrated intensities obtained from two Al-Zn alloys of different composition is reasonable compared with the quasi-equilibrium phase diagram.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1985-11-08
20巻
1号
開始ページ 35
終了ページ 43
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307157
JaLCDOI 10.18926/15770
フルテキストURL Mem_Sch_Eng_OU_15_2_29.pdf
著者 Ohta, Mutsuo| Kanadani, Teruto| 榊原 精| Yamada, Masuo|
抄録 Measurements of electrical resistivity and intensity of small-angle X-ray scattering and transmission electron microscopy were made on Al-Zn alloys of several compositions. G.P. zones are formed by the nucleation-and-growth mechanism above the spinodal temperature. The nucleus has a critical size for growth. This size becomes larger when aged at higher temperatures. The sizes of the G.P. zones formed by this mechanism distribute broadly, but those formed by the spinodal decomposition do closely. The spinodal temperatures estimated for Al-10.0, 12.5, 15.0, and 20.0wt % Zn alloys are ~95, ~110, ~130, and ~180℃, respectively. The critical temperatures below which G.P. zones are observed in these alloys are ~115, ~135, ~160, and ~210℃, respectively.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1981-03-30
15巻
2号
開始ページ 29
終了ページ 53
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307895
JaLCDOI 10.18926/15717
フルテキストURL Mem_Sch_Eng_OU_13_153.pdf
著者 Fukui, Kiyoshi| Nogi, Shigeji| Yamada, Masuo| Sakakibara, Akira|
抄録 A unified treatment of injection and mutual phase locking phenomena in microwave oscillators coupled by a network characterized by a Y-matrix is presented. Under certain simplifying assumptions, steady state solutions such as locking frequency and oscillation phase relation are given with emphasis placed on the coupling-network dependence of locking bandwidth. Also, some examples of locking system specified by y(21)=0, Y(21)= Y(12) and y21= -Y12 are briefly discussed.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 153
終了ページ 162
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307532
JaLCDOI 10.18926/15715
フルテキストURL Mem_Sch_Eng_OU_13_133.pdf
著者 Ohta, Mutsuo| Kanadani, Teruto| Yamada, Masuo| 榊原 精|
抄録 Aging and reversion in dilute Al-Ag alloys are studied by means of the measurements of electrical resistivity. Results obtained are as follows: 1) Increase in the as-quenched resistivity is found for a low quenching temperature. This increase may be due to the fluctuation of solute concentration at the quenching temperature. 2) When the fluctuation exists in the alloy, the aging rate becomes slow and the maximum resistivity in the isothermal aging curve becomes small as the vacancyconcentration becomes low. The maximum resistivity becomes large again when the vacancy concentration becomes further lower, and finally the maximum does not appear. 3) These behaviors are explained in terms of the difference in the rate of growth of the G.P. zones in the regions of higher and lower solute concentration induced by the fluctuation and in terms of the change of this difference with vacancy concentration. 4) G.P. zones may be formed by the spinodal decomposition with indefinite surfaces at first, grown to larger ones with difinite surfaces and changed to ordered nzones in the alloy. 5) It is confirmed that G.P. zones are formed by the nucleation-and-growth mechanism also in Al-Ag alloys above the spinodal temperature.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 133
終了ページ 152
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307468
JaLCDOI 10.18926/15712
フルテキストURL Mem_Sch_Eng_OU_13_119.pdf
著者 Ohta, Mutsuo| Yamada, Masuo| Kanadani, Teruto| 榊原 精|
抄録 The effects of the fluctuation of solute concentration on the process of aging in Al-10wt % Zn alloy were studied by measurements of the intensity of small-angle X-ray scattering and by electron microscopy. Specimen was quenched from a higher temperature(T(Ql), mainly 300℃) to an intermediate temperature (T(Q2), 110~230℃), held there for a time, quenched again into iced water and aged isothermally at 0℃ or 40℃. Results obtained are as follows: (1) When the specimen was held at T(Q2) for a sufficient time and aged at relatively high temperatue(e.g. Ihr at 125℃ and aged at 40℃), a two-step increasing of both resistivity and integrated intensity was found. (2) Each of the steps has characteristics of the formation of G.P. zones by the spinodal decomposition. (3) When the maximum resistivity(p(max)) takes a minimum, Size distribution of the G.P. zones, estimated from the difference between Guinier and Porod radii, is much broader than that at p(max) in the usual direct quenching. (4) When the holding time at T(Q2) is long enough, the size distribution at p(max) is as broad as that at p(max) in the usual case. (5) After a prolonged aging under the condition that P(max) takes minimum, G.P. zones grow markedly and become oblate ellipsoidal with a major axis of about 20nm. (6) These results are consistently understood in terms of the fluctuation of solute concentration at T(Q2) and the change in the concentration of vacancies during annealing at T(Q2). That is, it is considered that these results are due to the difference in aging behavior between the regions of relatively high concentration and the ones of low concentration induced by the fluctuation.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 119
終了ページ 132
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307931
JaLCDOI 10.18926/15709
フルテキストURL Mem_Sch_Eng_OU_13_95.pdf
著者 Ohta, Mutsuo| Kanadani, Teruto| Yamada, Masuo| 榊原 精|
抄録 Aging process in Al-Zn alloys was studied by the measurements of the electrical resistivity when the alloy was quenched from a high temperature, about 300℃ (the first quenching temperature), to an intermediate temperature, between 110℃ and 230℃ (the second quenching temperature), held at this temperature for a time, quenched again into iced water and aged at a low temperature. Variation of the holding time at the second quenching temperature brings about the variation of the isothermal aging curves. Maximum resistivity of the isothermal aging curve, p(max) , decreases at first, passes a minimum and then increases to reach a stationary value as the holding time at the intermediate temperature increases. It is pointed out that this phenomenon is mainly due to the fluctuation of solute concentration and the vacancy concentration decreasing at the intermediate temperature.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 95
終了ページ 117
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307526