1988 Fiscal Year Final Research Report Summary
Study on structural phase transition of alloys by mxvns of X-ray diffuse scattering
| Project/Area Number |
62580040
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
KITANO Yasuyuki Hiroshima University, Associate Professor, 理学部, 助教授 (20033855)
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| Co-Investigator(Kenkyū-buntansha) |
OHBA Takuya University of Tsukuba, Research Associate, 物質工学系, 助手 (00211110)
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| Project Period (FY) |
1987 – 1988
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| Keywords | X-ray diffraction / High temperatures / Diffuse scattering / X線高温回折装置 |
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| Research Abstract |
In order to measure X-ray diffracted intensities at high temperatures, a single crystal specimen-holder is constructed and attached to an automated four-circle-goniometer. A beryllium hemisphere is used as a window through which the X-rays pass. This instrument will be conveniently used for measurements of diffuse scattering observed in various solid solutions of metals which are in a state of so called short renge order.
A specimen-holder constructed here consists of four parts. The first part is a sample holder which is heated at high temperatures and is connected directly to the -axis of the four-circle-goniometer. This part is rotated independently from other part of the instrument. The second part is a heater which gives thermal radistions to the sample-holder. the electric current of the heater is controled to keep the specimen temperatures to be constant within 0.1K. The third part is a main capsule which keeps specimens in a high vacuum to privent from oxidation. The fourth part is a capsule hanger which plays a role to avoid loading torques to the -axis especially when angle of the x-axis becomes near 90 degrees. the highest temperature of the specimen achieved was 629K in a test experiment. The specimen temprature was stable within 0.1K when the heater was controled by the use of a commercial power supply with an SCR system.
The diffuse scattering from the -phase Ag-Al single orystal which was quenched from 473K into the iced water was re-examined. A specific distribution previously discovered was confirmed in the reciprocal space at the room temperature. In a preliminary experiment at 382K and 477K, the diffuse scattering is measured along four lines in the reciprocal space. The MoK X-ray was used as a source. About 17% of X-rays are absorped by the beryllium hemisphere. The diffuse peaks which had been observed at the room temperature befor heating have become smaller as the temperature increases, and they have vanished at 477K at all.
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