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Preparation Of Multi-Component Bulk Amorphous Alloys And Design Of Payload Experiments In Space

Posted on:2005-12-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q JingFull Text:PDF
GTID:1101360152495549Subject:Materials science
Abstract/Summary:PDF Full Text Request
Glass forming ability, preparation, microstructure and properties of multi-component bulk amorphous alloys have been studied in this thesis. From study of glass forming abilities of Ni-based and Zr-based alloys, ZrNiAl bulk amorphous alloy rods with a diameter of 8 mm were successfully prepared. Structure and property features of the prepared amorphous samples were examined by means of XRD, DSC, DTA, and SEM. Compressing experiments showed that the strength of ZrNiAl bulk amorphous alloy is more than 1.8 GPa and its largest elastic strain is more than 1.8 %. Relationship between eutectic transition and glass forming ability of alloys was confirmed. A long rod with a diameter of 20 mm and an aspect ratio of 20:1 of Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was prepared. Suitable temperature region for super-plastic deformation of the bulk amorphous alloy was determined by thermal expansion experiments, and the amorphous alloy was found to exhibit excellent super-plastic deformation ability in this temperature region. Thermal expansion behavior and relaxation of Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy were studied. In the first round of heating of the as-quenched amorphous sample, the expansion coefficient almost did not change below 200℃, which was about 9.26×10-6/℃. Above 200℃ the expansion coefficient of the as-quenched sample decreased to 7.39×10-6/℃ in 200-300℃. In the following repeated heating of the same sample, the expansion coefficient of the alloy kept almost unchanged which was almost the same as that of the crystallized sample. The expansion behaviors during aging of the amorphous alloy were also studied. It is found that structure relaxation of the bulk amorphous alloy hardly resulted in contraction of samples below 200℃. The procedure of space experiments on solidification of ZrTiCuNiBe amorphous alloy has been determined. Design of a canister of Get Away Special (GAS) for materials experiments in space, which is planned to be carried out on earth orbit by the US Space Shuttle, was also done and relative hardwares were made. The running tests of the canister were done successfully. The results showed that the hardwares, the temperature distribution in the furnaces, and the temperature environment in the whole canister are all in agreement with the project requirements.
Keywords/Search Tags:bulk amorphous alloy, glass forming ability, super-plastic deformation, thermal expansion, structure relaxation, material science in space
PDF Full Text Request
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