Cyclic-loading induced lattice-strain asymmetry in loading and transverse directions

E-Wen Huang*, Rozaliya I. Barabash, Bjørn Clausen, Peter K. Liaw

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Cyclic-loading effects on a nickel-based superalloy are investigated with in-situ neutron-diffraction measurements. The temperature evolution subjected to cyclic loading is estimated based on the lattice-strain evolution. The calculated thermoelastic responses are compared with the measured bulk temperature evolution. Two transitions in the temperature-evolution are bserved. The first transition, observed with the neutron-measurement results, is associated with the cyclic hardening/softening-structural transformation. The second transition is observed at a larger number of fatigue cycles. It has a distinct origin and is related to the start of irreversible structural transformations during fatigue. A lattice-strain asymmetry behavior is observed. The lattice-strain asymmetry is quantified as a grain-orientation-dependent transverse/loading parameter. This strain-asymmetry evolution reveals the irreversible plastic deformation subjected to fatigue. The irreversible fatigue phenomena might relate to the formation of the microcracks. At elevated temperatures, the cyclic hardening/softening transition starts at lower fatigue cycles as compared to room temperature. A comparison between the room-temperature and the elevated-temperature fatigue experiments is performed. The asymmetry-parameter evolutions show the same irreversible trends at both the room and elevated temperatures.

Original languageEnglish
Pages (from-to)1454-1461
Number of pages8
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume43
Issue number5
DOIs
StatePublished - 1 May 2012

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