Title page for etd-0724112-165735


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URN etd-0724112-165735
Author Liang-Jie Hung
Author's Email Address No Public.
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Department Materials and Optoelectronic Science
Year 2011
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Influence of hot rolling microstructure on mechanical properties of fullyannealed 5052 aluminum alloy
Date of Defense 2012-06-15
Page Count 87
Keyword
  • texture
  • aluminum alloy
  • annealing processes
  • yield strength
  • tensile ductility
  • Abstract The objective of this work is to investigate the influence of hot rolling process on the
    mechanical properties of AA 5052 aluminum alloy. Hot-rolled band fabricated by tandem
    mill (hot-band A) will be compared with that fabricated by reverse mill hot-band C).
    Optical microscopic observations revealed that hot-band A has a uniform microstructure
    throughout the thickness, while hot-band C exhibits non-uniform microstructure, fine
    grains near the surface and coarser grains in the center. Both hot-bands were subjected to
    cold-rolling and annealing to O-temper. Two annealing processes were used: (a) annealing
    in 500oC salt bath, which may simulate the high heating rate of continuous annealing line
    (CAL), and (b) annealing in 320oC conventional air furnace with heating rate of 30oC/h,
    which may simulate the slow heating rate of batch-type annealing. In general, both
    materials annealed in 320oC air furnace exhibit higher yield strength than those annealed in
    500oC salt bath do, however, both materials exhibit better tensile ductility after annealed in
    500oC salt bath as compared with those annealed in 320oC air furnace.TEM examinations
    indicated that the cold-rolled sheet after annealing in 320oC air furnace contains larger
    number of precipitates comparing with its 500oC salt bath annealed counterpart. This
    observation may account for the higher yield strength of cold-rolled sheet annealed in
    320oC air furnace. After cold-rolling and annealing in 320oC air furnace, the material C
    shows higher yield strength than the material A does. However, after annealing in 500oC
    salt bath, both materials have similar yield strength. XRD pole-figure analysis indicated
    that hot-band A exhibited stronger texture than hot-band C did. The texture intensity for
    both materials decreased considerably after cold-rolling and annealing. Orientation image
    mapping (OIM) obtained by EBSD (electron backscattered diffraction) analysis indicated
    that the grain boundaries in both materials after cold-rolling and annealing were mainly
    high angle boundaries, and the 500oC salt bath annealed specimens have more equiaxed
    grain shape as compared with the 320oC air furnace annealed specimens.
    Advisory Committee
  • Dr. Chih-Pu Chang - chair
  • Chung-Yi Yu - co-chair
  • Dr. Po-We Kao - advisor
  • Files
  • etd-0724112-165735.pdf
  • Indicate in-campus at 5 year and off-campus access at 99 year.
    Date of Submission 2012-07-24

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