Digital image correlation study of mechanical response of nickel superalloy Hastelloy X under thermal and mechanical cycling: Uniaxial and biaxial stress states

Bharath Swaminathan, John Lambros, Huseyin Sehitoglu

Research output: Contribution to journalArticlepeer-review

Abstract

The cyclic plastic strain accumulation of a dynamic strain aging Ni-based superalloy, Hastelloy X, is investigated using digital image correlation under both uniaxial and biaxial thermomechanical loading conditions. Thermal cycling and uniaxial mechanical tensile loading demonstrate that this material exhibits a Cottrell-Stokes-type response in which yield stress is not fully recovered after a mechanical loading cycle followed by a second isothermal loading cycle at elevated temperature (between room temperature and 600 °C in this work). The Portevin-Le Chatelier dynamic strain aging effect at higher temperatures, which has been seen to occur in this material, may also contribute to this reduction in flow stress. Additionally, under biaxial stress states introduced by means of a double-notch experimental sample, various cyclic thermal and mechanical loading combinations demonstrated a complex thermomechanical plastic response of this material. For example, cyclic thermal loading experiments at fixed displacement amounts for each cycle show greater plastic strain accumulation after three cycles when cycling is performed at a combination of 300 °C and 600 °C than that for three isothermal 600 °C cycles.

Original languageEnglish (US)
Pages (from-to)233-243
Number of pages11
JournalJournal of Strain Analysis for Engineering Design
Volume49
Issue number4
DOIs
StatePublished - May 2014

Keywords

  • High temperature
  • Portevin-Le Chatelier effect
  • cyclic plasticity
  • digital image correlation
  • notch

ASJC Scopus subject areas

  • Modeling and Simulation
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics

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