Loading...

Investigation of Mechanical Milling Effects on Al-Cu and Al-CuO Powder Mixture Morphological and Structural Characteristic and Mechanical Properties Changes Resultant from Age Hardening

Haghighatzadeh, Mehdi | 2009

767 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39233 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Simchi, Abdolreza
  7. Abstract:
  8. In the present work, nanocrystalline Al-4wt%Cu alloy reinforced with nanometric Al2O3 particles was synthesized by in-situ reactive milling of Al and CuO powder mixture and hot extrusion. The effect of nanometric Al2O3 particles on the aging behavior and mechanical properties of this alloy was investigated. During mechanical milling, copper oxide were reduced and dissolved in the aluminum lattice. consequently, Al(Cu) solid solution matrix was produced. Also, nanometric Al2O3 particles were also distributed in the matrix uniformly. The powder blend was then pressed in an Al can at 100 MPa pressure and subsequently extruded at 450 0C at the extrusion ratio of 16:1. The density of the sintered sample was measured by the water displacement (Archimedes) method. Similar to the nanocomposite, nanocrystalline Al-4wt%Cu alloy matrix was synthesized. X-ray diffraction (XRD) technique was employed to study the formation of Al-Cu solid solution. Mechanical milling stages and morphological changes were studied by scanning electron microscopy (SEM) and bulk density measurement. The grain refinement of the matrix by severe plastic deformation resulted in the formation of nanocrystalline Al-Cu alloy. It was determined that the FCC Al (Cu) solid solution has a lattice parameter of 4.05 A°, average crystallite size of about 65 nm and lattice strain of 0.30%. Compression experiments of the age-hardened specimens at their maximum possible hardness showed that the nanocomposite specimen has compression strength and yield strength of about 1.5 and 1.3 times of the Al-Cu alloy
  9. Keywords:
  10. Nanocomposite ; Age Hardening ; Mechanical Properties

 Digital Object List

 Bookmark

No TOC