Transient Phenomena Following Precipitation and Re-Solution Anneals in a NiTi Alloy

Abstract

Transient phenomena following anneals in a near stoichiometric NiTi alloy are investigated by means of differential scanning calorimetry (DSC). Precipitation anneals (350 deg C) raise the temperature range of the martensite and R-transformation. Subsequent cycling through the transformation range (-40 deg to 100 deg C) produces small changes in the martensite DSC peaks and no observable change in the R-peak. Subsequent re-solution anneals (600 deg C) produce dramatic effects: Ms rises approximately 20 deg C above its value preceding the precipitation anneal and the martensite DSC peak is very sharp and symmetric, while the R-transformation peak is not observable. During ensuing cycling, the martensite peak returns to its original form and position after about 300 cycles, and the R-peak appears after 4 cycles and is essentially invariant to cycling. The transient data are consistent with a dislocation model.... Differential scanning calorimetry, Shape memory alloys, Martensitic transformation, Phase transformation

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1993
Accession Number
ADA267557

Entities

People

  • Lawrence V. Meisel
  • Paul J. Cote

Organizations

  • United States Army Armament Research, Development and Engineering Center

Tags

Communities of Interest

  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Alloys
  • Annealing
  • Calorimetry
  • Critical Temperature
  • Dislocations
  • Electron Microscopy
  • Engineering
  • Heat Energy
  • Iron Alloys
  • Low Temperature
  • Martensite
  • Military Research
  • Phase Transformations
  • Precipitation
  • Security
  • Shape Memory Alloys
  • Standards

Fields of Study

  • Materials science

Readers

  • Control Systems Engineering.
  • Powder metallurgy of Titanium alloys.