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Title page for etd-0830113-105002


URN etd-0830113-105002 Statistics This thesis had been viewed 1207 times. Download 2 times.
Author Chang-Hung Hsien
Author's Email Address No Public.
Department Materials Engineering
Year 2012 Semester 2
Degree Master Type of Document Master's Thesis
Language zh-TW.Big5 Chinese Page Count 101
Title The Dimensional Change of A390 Al Alloy upon Aging Treatments
Keyword
  • dimensional stability
  • A390 alloy
  • A390 alloy
  • dimensional stability
  • Abstract In this study the dimensional stability in a hyper-eutectic A390 alloy, which is strengthened by adding an extra amount of 0.5% Mg and 0.23% Zr, is studied. In order to comprehend the dimension change in the A390 alloy, an Al2Cu(Mg) precipitate-bearing 2024 Al alloy and an Mg2Si precipitate-bearing 6061 Al alloy are used for the characterizations of dimensional change in the alloys when precipitation reactions take place. After realizing the basic dimensional change associated with the precipitation reaction, the aging behaviors and the dimensional change occurring in the T5 treatment of a direct chilled gravitation cast A390 alloy are examined. An optimum dimensional stabilized treatment was then determined. This set of optimum dimensional stabilized treatment was then applied to a direct chilled die casting A390 alloy cylinder. An in-situ measurement of the size and shape of the cylinder at elevated temperature are performed. The results show that in the course of aging treatment the lattice constant of Al-rich α phase and the size of the A390 alloy increase with increasing aging time. It was therefore concluded that the course for the dimensional change in the A390 alloy is due primarily to the precipitation of the Al2Cu(Mg) phase. In addition, from the results of measurement of cylinder at elevated temperature it was found that the dimensions of A390 alloy cylinder are stabilized by a T5 heat treatment under the condition of over-aging at 230oC for 1 hour. The over-aging treatment performed on the cylinder results to a stabilized cylinder with roundness and cylindricity values of 23 and 16 μm, respectively.
    Advisor Committee
  • Chih-Fu Yang - advisor
  • Chun-Mu Chen - co-chair
  • Sheng-Long Lee - co-chair
  • Files indicate in-campus access at 2 years and off-campus not accessible
    Date of Defense 2013-07-26 Date of Submission 2013-08-30


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