In-situ heating observations on microstructure relaxation of ultrafine-grained high-entropy alloys using neutron diffraction and laser-scanning confocal microscopy

Megumi Kawasaki, Jae Kyung Han, Suk Chun Moon, Klaus Dieter Liss

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

The thermal stability of ultrafine-grained metals can be fully understood when observing time-resolved microstructural changes over multiple-length scales. The global microstructural relaxation behavior upon heating of an ultrafine-grained (UFG) CoCrFeNi high-entropy alloy (HEA) was characterized by in-situ heating neutron diffraction measurements. Before heating, the nanocrystalline microstructure was introduced by applying high-pressure torsion (HPT), leading to severe lattice distortion by excess dislocations and defects. The sequential information on the structural relaxation of recovery, recrystallization, and grain growth are identified by in-situ heating neutron diffraction analysis defining the texture development, linear thermal lattice expansion, and stress relaxation behaviors of the UFG HEA with increasing temperature up to 1300K. By contrast, nanocrystalline metals processed by HPT are often inhomogeneous microstructurally and compositionally. The influence of such inhomogeneity on the macro-scale microstructural relaxation is monitored using an HPT-processed CoCrFeNiMn high-entropy alloy through in-situ heating laser-scanning confocal microscopy. This study emphasizes the importance of characterization techniques for further in-depth exploration of the SPD-processed ultrafinegrained structure.

Original languageEnglish
Title of host publicationICSAM 2023 - 14th International Conference on Superplasticity in Advanced Materials
EditorsJose-Maria Cabrera
PublisherAssociation of American Publishers
Pages235-243
Number of pages9
ISBN (Print)9781644902608
DOIs
StatePublished - 2023
Event14th International Conference on Superplasticity in Advanced Materials, ICSAM 2023 - Barcelona , Spain
Duration: 10 Jul 202312 Jul 2023

Publication series

NameMaterials Research Proceedings
Volume32
ISSN (Print)2474-3941
ISSN (Electronic)2474-395X

Conference

Conference14th International Conference on Superplasticity in Advanced Materials, ICSAM 2023
Country/TerritorySpain
CityBarcelona
Period10/07/2312/07/23

Keywords

  • High-Pressure Torsion
  • Laser-Scanning Confocal Microscopy
  • Nanostructure
  • Neutron Diffraction
  • X-Ray Diffraction

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