Loading...

An Investigation into the Effect of Solidification Rates and Melt Filtration on the Tensile Properties of A356 Castings

Khakzad Shahandashti, Arash | 2012

592 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43832 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Varahram, Naser; Davami, Parviz
  7. Abstract:
  8. A356 castings show different characteristics during tensile tests. This behavior emanates from casting defects such as pores and double oxide films. These defects lead to quick and unexpected failure during tensile tests. Secondary dendrite arm spacing of primary α phase, eutectic phase, volume fraction of pores and oxide films are the characteristics that affect the tensile property. N this study the effect of changing two characteristics on the microstructural constituents is investigated. The first one is cooling rates, and the second one is melt filtration by using different filter in the runner. According to the tensile properties, the effect of these changes on tensile properties is investigated. Changes of solidification time and tensile properties against secondary dendrite arm spacing are explained quantitatively. Trend of changes of quality index against dendrite arm spacing and volume fraction of pores is hypothesized as a linear function, so quantitative relations for estimating these parameters are presented. The Weibull analysis is used for investigation the effect of melt filtration on tensile properties and defects formed in the casting. According to results, castings accompanied by filters with smaller pores are more reliable, and they have more Weibull modulus and fewer defects. For clarifying this statement, forming and entrapping of double oxide films is explained by using the context of critical velocity of melt in the runner by using SutCast software results. Finally, SEM/EDX analysis is done on the fracture surfaces of the tensile specimens to observe the amount of oxide films in the sample
  9. Keywords:
  10. Tensile Properties ; Microstructure ; Aluminum Alloy A356 ; Weible Model ; Solidification Time ; Oxide Films

 Digital Object List

  • محتواي پايان نامه
  •   view

 Bookmark

No TOC