Effect of heat treatment on the microstructure, texture and elastic anisotropy of the nickel-based superalloy CM247LC processed by selective laser melting

Muñoz-Moreno, R. and Divya, V.D. and Driver, S. L. and Messé, O.M.D.M. and Illston, T. and Baker, S. and Carpenter, M. A. and Stone, H.J. (2016) Effect of heat treatment on the microstructure, texture and elastic anisotropy of the nickel-based superalloy CM247LC processed by selective laser melting. Materials Science and Engineering: B, 674. pp. 529-539. ISSN 0921-5107 DOI 10.1016/j.msea.2016.06.075

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Abstract

Selective laser melting (SLM) of nickel-based superalloys is of great interest for the aerospace industry due to its capability for producing components with complex geometries. However, an improved understanding of the effect of SLM and subsequent post deposition heat treatments on the microstructure and mechanical properties is required to ensure that components with good structural integrity are produced. In this study, the microstructure, texture and elastic anisotropy of the nickel-based superalloy, CM247LC, in the as-SLM and heat-treated states have been analysed. The as-SLM microstructure showed fine elongated cells with a preferential alignment of <001> along the build direction and a significant intercellular misorientation. Heat treatments at temperatures below 1230 °C resulted in a progressive recovery of the microstructure, whilst heat treatments above this temperature gave rise to a recrystallised microstructure. The extent to which nucleation and growth of the γ′ precipitates and secondary particles were affected by increasing the heat treatment temperature was also characterised. The bulk elastic anisotropy of all samples was measured by resonant ultrasound spectroscopy (RUS) and was found to be consistent with the local textures obtained by electron backscatter diffraction (EBSD). It was observed that the initially strong elastic anisotropy exhibited by the as-SLM material was significantly reduced in the recrystallised samples, although some anisotropy was retained as a result of their elongated grain microstructures.

Item Type:	Article
Uncontrolled Keywords:	2016AREP; IA71
Subjects:	03 - Mineral Sciences
Divisions:	03 - Mineral Sciences
Journal or Publication Title:	Materials Science and Engineering: B
Volume:	674
Page Range:	pp. 529-539
Identification Number:	10.1016/j.msea.2016.06.075
Depositing User:	Sarah Humbert
Date Deposited:	20 Sep 2016 17:02
Last Modified:	20 Sep 2016 17:02
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3753

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