Strengthening behavior in non-isothermal monotonic and cyclic loading in a Ni-based single crystal superalloy Academic Article uri icon

abstract

  • 2016 Elsevier Ltd Dwell-fatigue tests and variable strain rate tensile tests followed by cycling tests were performed using 001-oriented specimens made of a first-generation Ni-based single crystal superalloy. A short thermal jump from the nominal temperature of 1050 to 1200C was introduced along the lifetime of dwell-fatigue experiments and at the beginning of tensile tests. A fine precipitation occurred in the matrix upon such event which induced a large transient strengthening effect on the mechanical properties. In fact, a transient decrease of the plastic strain rate, corresponding to a reduced magnitude in the hysteresis loops, was measured after the temperature peak during the dwell-fatigue experiments. In addition, a temperature peak produced a large hardening effect and a mechanical behavior change during the tensile tests since a hardening of 160MPa was recorded and a perfectly plastic behavior was obtained. These transient phenomena were due to a temporary additional strengthening provided by fine precipitates lasting for the time necessary to not hinder dislocation motions anymore. Furthermore, the experimental results were also used to determine how fine precipitates modified the magnitude and the saturation speed of the isotropic and kinematic hardenings.

published proceedings

  • INTERNATIONAL JOURNAL OF FATIGUE

author list (cited authors)

  • le Graverend, J., Cormier, J., Gallerneau, F., Kruch, S., & Mendez, J.

citation count

  • 12

complete list of authors

  • le Graverend, Jean-Briac||Cormier, Jonathan||Gallerneau, Franck||Kruch, Serge||Mendez, Jose

publication date

  • January 2016