Detail publikace

Microstructural instability of L-PBF Co-28Cr-6Mo alloy at elevated temperatures

ROUDNICKÁ, M. MOLNÁROVÁ, O. DRAHOKOUPIL, J. ŠREIBR, V. PALOUŠEK, D. VOJTĚCH, D.

Anglický název

Microstructural instability of L-PBF Co-28Cr-6Mo alloy at elevated temperatures

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

en

Originální abstrakt

In relation to the production of complex aircraft components, the additive manufacturing (AM) of Co-28Cr-6Mo alloy is highly discussed as it could bring many benefits regarding new designs, components lightening and shortening the design-to-product period. However, such components must undergo strict requirements for mechanical properties and material stability, even at elevated temperatures which might occur during part operation. So far, little is known about the thermal stability of Co-28Cr-6Mo alloy when produced by laser powder bed fusion (L-PBF), one of the mostly used AM technologies. In the present study, we reveal the instability of this material already at temperatures above 673 K. Material hardening accompanied with a significant loss of plasticity is caused by the breakdown of fine cellular microstructure with intercellular Mo segregation, precipitation of sigma-phase and phase transformation of the matrix. Detail characterization by transmission electron microscopy was carried out for the maximum hardness state obtained after annealing the alloy at 1173 K for 5 h. The important findings of this study, representing an operational risk for L-PBF Co-28Cr-6Mo alloy, call for subsequent research into suitable heat treatment that would induce the stability of the material.

Anglický abstrakt

In relation to the production of complex aircraft components, the additive manufacturing (AM) of Co-28Cr-6Mo alloy is highly discussed as it could bring many benefits regarding new designs, components lightening and shortening the design-to-product period. However, such components must undergo strict requirements for mechanical properties and material stability, even at elevated temperatures which might occur during part operation. So far, little is known about the thermal stability of Co-28Cr-6Mo alloy when produced by laser powder bed fusion (L-PBF), one of the mostly used AM technologies. In the present study, we reveal the instability of this material already at temperatures above 673 K. Material hardening accompanied with a significant loss of plasticity is caused by the breakdown of fine cellular microstructure with intercellular Mo segregation, precipitation of sigma-phase and phase transformation of the matrix. Detail characterization by transmission electron microscopy was carried out for the maximum hardness state obtained after annealing the alloy at 1173 K for 5 h. The important findings of this study, representing an operational risk for L-PBF Co-28Cr-6Mo alloy, call for subsequent research into suitable heat treatment that would induce the stability of the material.

Klíčová slova anglicky

Co-28Cr-6Mo; Additive manufacturing; Laser powder bed fusion; Elevated temperature operation

Vydáno

15.05.2021

Nakladatel

ELSEVIER

Místo

AMSTERDAM

ISSN

2214-7810

Ročník

44

Číslo

44

Strany od–do

1–16

Počet stran

16

BIBTEX


@article{BUT175115,
  author="Orsolya {Molnárová} and Michaela {Roudnická} and Jan {Drahokoupil} and Vít {Šreibr} and David {Paloušek} and Dalibor {Vojtěch} and Michaela {Roudnická},
  title="Microstructural instability of L-PBF Co-28Cr-6Mo alloy at elevated temperatures",
  year="2021",
  volume="44",
  number="44",
  month="May",
  pages="1--16",
  publisher="ELSEVIER",
  address="AMSTERDAM",
  issn="2214-7810"
}