Microstructure Control and Improved Mechanical Properties of Al-Si-Cu-Fe Alloy by Deformation-Semi-Solid Casting Process
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Accession number;05A0709858
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| Title;Microstructure Control and Improved Mechanical Properties of Al-Si-Cu-Fe Alloy by Deformation-Semi-Solid Casting Process |
| Author;
SATO TATSUO
(Tokyo Inst. Technology, Graduate School of Sci. and Engineering, JPN)
UENO HITOSHI
(Tokyo Inst. Technology, Graduate School of Sci. and Engineering, JPN)
TEZUKA HIROYASU
(Tokyo Inst. Technology, Graduate School of Sci. and Engineering, JPN)
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Journal Title;Journal of Japan Foundry Engineering Society
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Journal Code:G0096A
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ISSN:1342-0429
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VOL.77;NO.8;PAGE.547-553(2005)
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| Figure&Table&Reference;FIG.9, REF.4 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;The microstructure control and formation behavior of the characteristic microstructures in high Fe content aluminum cast alloy of Al-7%Si-3%Cu-1%Fe during the deformation-semi-solid casting process (D-SSC process) proposed in this work were investigated. The mechanical properties of the fabricated alloy by the D-SSC process were also examined. In the microstructures, the size and shape of the primary .ALPHA.-Al phase and the Fe containing intermetallic compound of the .BETA.-Al5FeSi phase were evaluated. The refined distribution of the .BETA. phase and finely spheroidized .ALPHA.-Al phase were simultaneously achieved by the D-SSC process which includes hot-deformation, heating to the semi-solid temperatures and casting. The increased total deformation ratio by the hot-rolling and final deformation ratio result in the decreased size of the .ALPHA.-Al phase after heating at temperatures of the semi-solid state. The .BETA. phase decreases mores as the total deformation ratio increases. The continuous in-situ observation of the microstructure changes during heating to the semi-solid temperature after hot-deformation was performed using a laser microscope. The recrystallized microstructure of the .ALPHA.-Al phase is first formed and the preferential dissolution of the recrystallized grain boundaries occurs shortly before the dissolution of the eutectic phase with increasing temperature. After dissolution of the grain boundaries, the separation and spheroidization of the .ALPHA.-Al phase occur, after which the characteristic semi-solid microstructure is formed. Deformation by hot-forging and the subsequent semi-slid casting process produce the more refined .BETA. phase, which is very effective for achieving excellent mechanical properties of the proof stress of 120 MPa, tensile strength of 265 MPa and elongation of 20%. The proposed D-SSC process is found to be useful for modifying the high amount of Fe into a harmless impurity. (author abst.) |
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