Loading...

Investigation of Effect of Temperature and Tension on Precipitation Behavior of AEREX350 Superalloy

Samaee Aghmiyoni, Vahid | 2011

553 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42388 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Asgari, Sirous
  7. Abstract:
  8. AEREX350 is a wrought Ni-Co base superalloy which was first developed as a fastener alloy and is a member of MP family of alloys which are thermo-mechanically processed. Due to chemical composition of AEREX350, the alloy benefits from precipitation hardening and solid solution strengthening as well as cold working and can be used in higher temperatures. To investigate the effect of deformation during precipitation, solution-treated samples was underwent hot compression test up to strain of 0.5 at range 650-800˚C, range of γ΄ formation. It is seen that work-hardening and deformation mechanism of high temperature deformation is slip and as a result its structure is dislocation but in room temperature, twining is the major mechanism of deformation and work-hardening. Over all work-hardening rate of samples increase with increasing of temperature which it associate to Suzuki effect and reduction of stacking fault energy regarding to increment of concentration of solute atoms in stacking faults. Decrement of work-hardening rate during deformation in 800˚C and reaching to fixed value during deformation in 750˚C can be related to activation of some high energy mechanisms of work softening, for instance stair-rod dislocations, and initiation of instability of stacking faults about 800˚C. It was, also, seen that precipitates grows faster during deformation than static precipitation. Room temperature strength of samples overall is more than static precipitated samples which can be related to addition of dislocation structure to microstructure. In sample which deformed in 800˚C, increment of strength is more than other samples which can be said that the size of γ΄ precipitate add more strength to material. Yield point of samples increase with temperature which can be related to precipitation of γ΄ in 750 and 800˚C, although in samples deformed at 750˚C until strain of 0.5, γ΄ was not seen but it is possible that γ΄ precipitates were not detected by TEM
  9. Keywords:
  10. Precipitation ; Work Hardening ; Hot Compression ; Aerex 350 Superalloy ; Gamma Prim Phase ; Transmission Electron Microscope

 Digital Object List

 Bookmark

No TOC