Tensile deformation micro-mechanisms of a polycrystalline nickel base superalloy: From jerky flow to softening

Rai, R K and Sahu, J K and Paulose, N and Fernando, D.C (2021) Tensile deformation micro-mechanisms of a polycrystalline nickel base superalloy: From jerky flow to softening. Materials Science and Engineering A, 807 .

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Abstract

In this study, efforts were made to elucidate the tensile deformation micro-mechanisms of a polycrystalline nickel-base superalloy used for the fabrication of critical rotating and stationary components of the gas turbine engine under relevant service conditions. The microstructural evolutions during the investigated temperatures and strain-rates are explicitly indicating the divergence in associated tensile responses. The alloy exhibits serrated or jerky flow behavior at 300 and 400 degrees C, whereas, yield strength anomaly (YSA) is observed at 750 degrees C. With further increase in testing temperature, softening mechanisms start dominating and dynamic recrystallization occurs at 930 degrees C. TEM investigation revealed that the serration in the flow curve at 300 degrees C is attributed to the disordering of the secondary.' -precipitates by the leading a/2 <110> dislocation super-partial and refurbishment of order through thermal activation before the trailing super-partial arrives. The YSA observed at 750 degrees C is essentially due to the cross-slip of dislocation super-partials and the presence of dislocation debris.

Item Type:Article
Official URL/DOI:https://doi.org/http://10.1016/j.msea.2021.140905
Uncontrolled Keywords:Deformation micro-mechanisms; TEM; Tension test; Jerky flow; Yield strength anomaly
Divisions:Material Science and Technology
ID Code:8339
Deposited By:Sahu A K
Deposited On:20 Apr 2021 15:42
Last Modified:20 Apr 2021 15:42
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