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Strength ductility paradox in a directionally solidified nickel base superalloy

IR@NML: CSIR-National Metallurgical Laboratory, Jamshedpur

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Title Strength ductility paradox in a directionally solidified nickel base superalloy
 
Creator Rai, R K
Sahu, J K
 
Subject Materials Science
 
Description In contrast to other structural alloys, yield strength of nickel base superalloys either remains constant or increases with temperature up to 700–800 °C making them more suitable for high temperature structural applications. However, the increase in yield strength is usually accompanied by a decrease in ductility. The results of the present investigation describe the substurural evolution in a directionally solidified nickel base superalloy CM 247 DS LC during tensile deformation, where ductility is not impaired even when yield strength is highest (at 750 °C). Extensive TEM studies offer plausible dislocation based mechanisms for retention of high ductility at 750 °C. The highest yield strength is attributed to the presence of intersecting faults along with partials bounded by anti-phase boundary. However, high ductility is due to the formation of SISF inside γ′ precipitates. These mechanisms provide necessary impetus for further alloy development.
 
Publisher Elsevier
 
Date 2018
 
Type Article
PeerReviewed
 
Relation http://eprints.nmlindia.org-7799
http://eprints.nmlindia.org/7799/
 
Identifier Rai, R K and Sahu, J K (2018) Strength ductility paradox in a directionally solidified nickel base superalloy. Materials Letters, 220 (IF-2.687). pp. 90-93.