Publication detail

Heat treatment of laser powder-bed-fused Co-28Cr-6Mo alloy to remove its microstructural instability by massive FCC -> HCP transformation

ROUDNICKÁ, M. KUBÁSEK, J. PANTĚLEJEV, L. MOLNÁROVÁ, O. BIGAS, J. DRAHOKOUPIL, J. PALOUŠEK, D. VOJTĚCH, D.

English title

Heat treatment of laser powder-bed-fused Co-28Cr-6Mo alloy to remove its microstructural instability by massive FCC -> HCP transformation

Type

journal article in Web of Science

Language

en

Original abstract

Laser powder bed fusion (L-PBF) of Co-28Cr-6Mo alloy is a powerful tool for many engineering applications but one has to be familiar with its microstructural instability in the as-produced state. In our previous study [Roudnicka et al., Additive Manuf. 44 (2021) 102025], we depicted the phenomenon of this instability when exposing the material to temperatures above 673 K. Microstructural changes bringing about hardening of the material were studied thoroughly. In the present study, we follow up by revealing the effect of this hardening on mechanical properties in tension and show the beneficial effect of heat treatment on removing the observed instability. Hardening associated with increasing the proportion of HCP epsilon-phase and with the precipitation of sigma-phase has a detrimental effect on material plasticity and can be negatively affect the fatigue too. We thus applied a two-stage heat treatment comprising solution annealing at 1473 K/2 h and aging at 1173 K/5 h. Not only it induced material stability but also increased the material strength with not such a detrimental decrease in material plasticity as was brought by direct aging at 1173 K/5 h.

English abstract

Laser powder bed fusion (L-PBF) of Co-28Cr-6Mo alloy is a powerful tool for many engineering applications but one has to be familiar with its microstructural instability in the as-produced state. In our previous study [Roudnicka et al., Additive Manuf. 44 (2021) 102025], we depicted the phenomenon of this instability when exposing the material to temperatures above 673 K. Microstructural changes bringing about hardening of the material were studied thoroughly. In the present study, we follow up by revealing the effect of this hardening on mechanical properties in tension and show the beneficial effect of heat treatment on removing the observed instability. Hardening associated with increasing the proportion of HCP epsilon-phase and with the precipitation of sigma-phase has a detrimental effect on material plasticity and can be negatively affect the fatigue too. We thus applied a two-stage heat treatment comprising solution annealing at 1473 K/2 h and aging at 1173 K/5 h. Not only it induced material stability but also increased the material strength with not such a detrimental decrease in material plasticity as was brought by direct aging at 1173 K/5 h.

Keywords in English

Co-28Cr-6Mo; Additive manufacturing; Laser powder bed fusion; Elevated temperatures operation; Heat treatment

Released

25.04.2021

Publisher

ELSEVIER

Location

AMSTERDAM

ISSN

2214-8604

Volume

47

Number

2021

Pages from–to

1–14

Pages count

14

BIBTEX


@article{BUT177082,
  author="Michaela {Roudnická} and Jiří {Kubásek} and Libor {Pantělejev} and Orsolya {Molnárová} and Jiří {Bigas} and Jan {Drahokoupil} and David {Paloušek} and Dalibor {Vojtěch},
  title="Heat treatment of laser powder-bed-fused Co-28Cr-6Mo alloy to remove its microstructural instability by massive FCC -> HCP transformation",
  year="2021",
  volume="47",
  number="2021",
  month="April",
  pages="1--14",
  publisher="ELSEVIER",
  address="AMSTERDAM",
  issn="2214-8604"
}