Deformation mechanisms in an additively manufactured dual-phase eutectic high-entropy alloy

Jie Ren, Margaret Wu, Chenyang Li, Shuai Guan, Jiaqi Dong, Jean Baptiste Forien, Tianyi Li, Katherine S. Shanks, Dunji Yu, Yan Chen, Ke An, Kelvin Y. Xie, Wei Chen, Thomas Voisin, Wen Chen

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Nanostructured metals and alloys often exhibit high strengths but at the expense of reduced ductility. Through harnessing the far-from-equilibrium processing conditions of laser powder-bed fusion (L-PBF) additive manufacturing, we develop a dual-phase nanolamellar structure comprised of FCC/L12 and BCC/B2 phases in a Ni40Co20Fe10Cr10Al18W2 eutectic high-entropy alloy (EHEA), which exhibits a combination of ultrahigh yield strength (>1.4 GPa) and large tensile ductility (∼17%). The deformation mechanisms of the additively manufactured EHEA are studied via in-situ synchrotron X-ray diffraction and high-resolution transmission electron microscopy. The high yield strength mainly results from effective blockage of dislocation motion by the high density of lamellar interfaces. The refined nanolamellar structures and low stacking fault energy (SFE) promote stacking fault (SF)-mediated deformation in FCC/L12 nanolamellae. The accumulation of abundant dislocations and SFs at lamellar interfaces can effectively elevate local stresses to promote dislocation multiplication and martensitic transformation in BCC/B2 nanolamellae. The cooperative deformation of the dual phases, assisted by the semi-coherent lamellar interfaces, gives rise to the large ductility of the as-printed EHEA. In addition, we also demonstrate that post-printing heat treatment allows us to tune the non-equilibrium microstructures and deformation mechanisms. After annealing, the significantly reduced SFE and thicknesses of the FCC nanolamellae facilitate the formation of massive SFs. The dissolution of nano-precipitates in the BCC/B2 nanolamellae reduces spatial confinement and further promotes martensitic transformation to enhance work hardening. Our work provides fundamental insights into the rich variety of deformation mechanisms underlying the exceptional mechanical properties of the additively manufactured dual-phase nanolamellar EHEAs.

Original languageEnglish
Article number119179
JournalActa Materialia
Volume257
DOIs
StatePublished - Sep 15 2023

Funding

Wen Chen at UMass Amherst acknowledges support from the US National Science Foundation (DMR-2004429 and DMR-2238204) and UMass Amherst Faculty Startup Fund. M.W. J.B. F. and T.V.’s work at Lawrence Livermore National Laboratory (LLNL) was performed under the auspices of the U.S. Department of Energy (DOE) under Contract No. DE-AC52–07NA27344. M.W. and T.V. would like to thank Tony Li at LLNL for helping with PED crystal orientation mapping. Wei Chen at Illinois Institute of Technology acknowledges support from the US National Science Foundation (DMR-1945380). In-situ high-energy X-ray diffraction work was carried out at the Advanced Photon Source (Beamline 11-ID-C and 1-ID-E), which is a US DOE user facility at Argonne National Laboratory. Authors would like to thank Jun-Sang Park at beamline 1-ID-E and Kevin A. Beyer at beamline 11-ID-C for the support. Some work is based on research conducted at the Center for High-Energy X-ray Sciences (CHEXS) at CHESS, which is supported by the National Science Foundation (BIO, ENG and MPS Directorates) under award DMR-1829070. Dr. Amlan Das’ experimental support at CHEXS is acknowledged. This research also used Spallation Neutron Source (SNS), which is a US DOE user facility at the Oak Ridge National Laboratory (ORNL), sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences. Wen Chen at UMass Amherst acknowledges support from the US National Science Foundation (DMR-2004429 and DMR-2238204) and UMass Amherst Faculty Startup Fund. M.W., J.B. F., and T.V.’s work at Lawrence Livermore National Laboratory (LLNL) was performed under the auspices of the U.S. Department of Energy (DOE) under Contract No. DE-AC52–07NA27344. M.W. and T.V. would like to thank Tony Li at LLNL for helping with PED crystal orientation mapping. Wei Chen at Illinois Institute of Technology acknowledges support from the US National Science Foundation (DMR-1945380). In-situ high-energy X-ray diffraction work was carried out at the Advanced Photon Source (Beamline 11-ID-C and 1-ID-E), which is a US DOE user facility at Argonne National Laboratory. Authors would like to thank Jun-Sang Park at beamline 1-ID-E and Kevin A. Beyer at beamline 11-ID-C for the support. Some work is based on research conducted at the Center for High-Energy X-ray Sciences (CHEXS) at CHESS, which is supported by the National Science Foundation (BIO, ENG and MPS Directorates) under award DMR-1829070. Dr. Amlan Das’ experimental support at CHEXS is acknowledged. This research also used Spallation Neutron Source (SNS), which is a US DOE user facility at the Oak Ridge National Laboratory (ORNL), sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences.

Keywords

  • Additive manufacturing
  • High-entropy alloy
  • In-situ synchrotron X-ray diffraction
  • Mechanical property
  • Nanolamellar structure

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