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The Effect of Deformation in Grooved Die and Heat Treatment on Formability and Mechanical Properties of a Precipitation Hardenable Aluminum Alloy

Dabbaghian, Mohammad Ali | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54407 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Karimi Taheri, Ali; Serajzadeh, Siamak
  7. Abstract:
  8. The precipitation hardenable 7075 Aluminum Alloy is one of the most important heat-treated aluminum alloys. The high strength of this alloy has led to its widespread use in the manufacture of various components in the automotive, aerospace, marine, defense and military industries. Although the production costs of this alloy sheet are high, but since the 7075 aluminum alloy has the capacity to be as strong as steels, by reducing the production process and thus reducing production costs, this alloy can be used more widely in various industries. Therefore, in this study, the mechanical properties of the 7075 aluminum sheet are improved by a new quenching method in the die (HFDQ), which is a thermomechanical process using severe plastic deformation of CGP. In this way, the sheets of the mentioned alloy remains for a certain period of time at the annealing temperature until a solid single-phase state is achieved. Immediately after this treatment, the hot sheet is subjected to the severe deformation process at room temperature. The mechanical properties the processed sheet are evaluated using simple tensile test, hardness test, anisotropy texture examinations. Also, the effect of aging on the behavior of mechanical properties of the alloy is investigated. Moreover, the results are interpreted by the metallography using light microscopes, field emission scanning electron microscope and EDS analyses. It was found that the best conditions for mechanical properties are related to the sample of two passes of HFDQ process with annealing between the passes and the initial solution of temperature and time of 470 ° C and 4 hours, respectively. Finally, due to the reduction of processing time and stages, increase of formability during deformation, the desired properties of strength and formability at ambient temperature due to the formation of fine-grained microstructure, the formation of fine precipitations and their uniform distribution in the matrix as well as the texture of gamma fiber generated in the sheet, the HFDQ process combined with severe deformation with CGP was recommended for enhancing the mechanical properties of the 7075 aluminum alloy sheet
  9. Keywords:
  10. Formability ; Heat Treatment ; Mechanical Properties ; Precipitation Hardenable Aluminum Alloy ; Constrained Groove Pressing (CGP) ; Hot Forming Die Quenching (HFDQ) ; Sheet Texture

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