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Appraising Forgeability and Surface Cracking in New Generation Cast and Wrought Superalloys

Published version
Peer-reviewed

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Authors

Fernandez-Alvarez, M 
Vaasudevan, A 
Fischer, E 
Rae, C 
Witulski, T 

Abstract

jats:titleAbstract</jats:title> jats:pSurface cracking poses a major problem in industrial forging, but the scientific understanding of the phenomenon is hampered by the difficulty of replicating it in a laboratory setting. In this work, a novel laboratory-scale experimental method is presented to investigate forgeability in new generation cast and wrought superalloys. This new approach makes possible appraising the prevalence and severity of surface cracking by mimicking the die chilling effects characteristic of hot die forging. Two high jats:italicγ</jats:italic>′-reinforced alloys are used to explore this methodology. A Gleeble thermo-mechanical simulator is used to conduct hot compression tests following a non-isothermal cycle, with the aim to simulate the cooling of the near-surface regions during the forging process. FEA simulations, sample geometry design, and heat-treatments are used to ensure the correspondence between laboratory and real-scale forging. A wide range of surface cracking results are obtained for different forging temperatures and cooling rates—proving the soundness of the method. Surprisingly, samples heated up to higher initial temperatures typically show more extensive surface cracking. These findings indicate that—along with the local mechanical conditions of the forging—die-chilling effects and forging temperatures are paramount in controlling surface cracking, as they dictate the key variables governing the distribution and kinetics of jats:italicγ</jats:italic>′ formation.</jats:p>

Description

Keywords

4014 Manufacturing Engineering, 40 Engineering

Journal Title

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Conference Name

Journal ISSN

1073-5623
1543-1940

Volume Title

54

Publisher

Springer Science and Business Media LLC