Influence of solidification cell structure on the martensitic transformation in additively manufactured steels

Felicity S.H.B. Freeman, Jo Sharp, Jiawei Xi, Iain Todd

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

A key feature when using martensitic steels is the proportion of retained austenite present in the final component. Martensitic steels manufactured by laser powder-bed fusion (LPBF) have been shown to have more retained austenite than when conventionally manufactured. The LPBF microstructure is characterised by small grains containing ultrafine solidification cells (<1 μm). This study shows that the solidification cells can fully suppress thermal martensite. The retained austenite is highly metastable, and will readily transform to deformation martensite either in-build from thermal strain or post-build from deformation. This raises concerns around sample preparation methods causing incorrect phase quantification in LPBF-built martensitic steels.

Original languageEnglish
Article number100917
Number of pages7
JournalAdditive Manufacturing
Volume30
Early online date24 Oct 2019
DOIs
Publication statusPublished - 1 Dec 2019
Externally publishedYes

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