Inhomogeneous strain and recrystallisation of a shot-peened Inconel 625 alloy after annealing

Microstructural variations in a shot-peened nickel superalloy after isothermal annealing were observed via scanning electron microscopy and electron backscatter diffraction analysis. The analysis was based on inverse pole figure and kernel average misorientation maps. Before annealing, a heavily pla...

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Bibliographic Details
Published inMaterials science and technology Vol. 35; no. 15; pp. 1856 - 1863
Main Authors Kumagai, Masayoshi, Kimura, Kazuki, Shimada, Naoki, Ishiwata, Masato
Format Journal Article
LanguageEnglish
Published London, England Taylor & Francis 13.10.2019
SAGE Publications
Subjects
EBSD
inhomogeneous strain
Nickel alloy
recrystallisation
shot peening
thermal annealing
thermal annealing
shot peening
inhomogeneous strain
recrystallisation
Nickel alloy
EBSD
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Summary:Microstructural variations in a shot-peened nickel superalloy after isothermal annealing were observed via scanning electron microscopy and electron backscatter diffraction analysis. The analysis was based on inverse pole figure and kernel average misorientation maps. Before annealing, a heavily plastically deformed layer was observed under the surface. Post annealing for 1 h, the uppermost 30-40 µm layer was discontinuously recrystallised and inhomogeneous strains remained in the below layers. After a particular duration, the inhomogeneous strains recovered but did not recrystallise. The threshold depth of recrystallisation depended on the inhomogeneous strains. Recrystallisation and growth progressed from the recrystallisation-threshold depth toward the surface. These microstructural variations explain the release mechanism of the residual stress induced by shot peening.
ISSN:0267-0836
1743-2847
DOI:10.1080/02670836.2019.1651475