Abstract
Additive manufacturing produces net-shaped components layer by layer for engineering applications1–7. The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling2,6, which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility3. Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 per cent, which surpasses those of other state-of-the-art additively manufactured metal alloys. The high yield strength stems from the strong strengthening effects of the dual-phase structures that consist of alternating face-centred cubic and body-centred cubic nanolamellae; the body-centred cubic nanolamellae exhibit higher strengths and higher hardening rates than the face-centred cubic nanolamellae. The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties.
Original language | English |
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Pages (from-to) | 62-68 |
Number of pages | 7 |
Journal | Nature |
Volume | 608 |
Issue number | 7921 |
DOIs | |
State | Published - Aug 4 2022 |
Funding
We thank D. Follette, P. Hou, M. Wu, K. A. Beyer and M. J. Frost for their experimental assistance. W.C. acknowledges support from the US National Science Foundation (DMR-2004429) and UMass Amherst Faculty Startup Fund. T.Z. acknowledges support from the US National Science Foundation (DMR-1810720 and DMR-2004412). Y.M.W. acknowledges support from the US National Science Foundation (DMR-2104933). T.V. acknowledges support from the Laboratory Directed Research and Development (LDRD) programme (21-LW-027) at Lawrence Livermore National Laboratory (LLNL). His work was performed under the auspices of the US Department of Energy (DOE) by LLNL under contract no. DE-AC52-07NA27344. In situ neutron-diffraction work was carried out at the 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. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US DOE Office of Science User Facility at ORNL. We thank J. Burns for assistance in performing the APT sample preparation and running the APT experiments. This research also used high-energy X-ray resources of the Advanced Photon Source (Beamline 11-ID-C), a US DOE Office of Science User Facility operated at Argonne National Laboratory under contract number DE-AC02-06CH11357.