Synthesis of precipitation-strengthened Al-Sc, Al-Zr and Al-Sc-Zr alloys via selective laser melting of elemental powder blends

Jennifer A. Glerum, Christoph Kenel, Tao Sun, David C. Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

Selective laser melting is used to create Al-1.5Sc, Al-1.5Zr and Al-0.75Sc-0.75Zr (at.%) alloys from blends of elemental Al, Sc, and Zr powders. This study investigates elemental alloying elements (Sc and Zr) which are high-melting and highly reactive, unlike previous work which focused on more concentrated elemental additions of lower-melting, lower-reactivity Cu and Si to aluminum. High-speed in situ synchrotron x-ray imaging and diffraction show that the 20−30 μm Al, Sc, and Zr powders fully melt and sufficiently mix in the molten state to create, on solidification, a homogeneous distribution of primary, micron-size L12 precipitates (Al3Sc, Al3Zr, and Al3(Sc,Zr), respectively) and nucleate micron-size Al matrix grains, as confirmed by SEM imaging of cross-sections. A second laser pass, simulating a realistic additive-manufacturing build condition, fully remelts the initial volume which shows, after solidification, the same Al3(Sc,Zr) L12 primary micro-precipitates and very fine Al grains. After aging at 300−400°C, the alloys show large increases in hardness, consistent with an exceptionally high number density (1.4 × 1024 m−3) and volume fraction (2.5%) of secondary Al3(Sc,Zr) nano-precipitates with a Sc-rich core and Zr-rich shell, as measured via atom-probe tomography.

Original languageEnglish (US)
Article number101461
JournalAdditive Manufacturing
Volume36
DOIs
StatePublished - Dec 2020

Funding

This research received funding from the US Army Research Laboratory (award W911NF-19-2-0092) and from the Argonne National Laboratory (ANL) via a Laboratory Directed Research and Development (LDRD) project with Dr. Jon Almer. JAG was supported by the Army Research Laboratory (ARL) Oak Ridge Associated Universities (ORAU) via a Journeyman Fellowship grant. This work made use of the EPIC facility of Northwestern University's NUANCE Center and the Northwestern University Center for Atom-Probe Tomography (NUCAPT), which have received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI (DMR-0420532) and ONR-DURIP (N00014-0400798, N00014-0610539, N00014-0910781, N00014-1712870) programs. This work also made use of the Materials Characterization and Imaging Facility which receives support from the MRSEC Program (NSF DMR-1720139) of the Materials Research Center at Northwestern University. The authors thank Dr. Jon-Erik Mogonye (U.S. Army Research Laboratory, Adelphi) for numerous useful discussions, Dr. Binna Song (NU), Ms. Kristen Scotti (NU), Mr. Sean Wang (NU), Dr. Andrew Chuang (ANL), Dr. Niranjan Parab (ANL), and Dr. Cang Zhao (ANL) for assistance with in situ imaging experiments, Mr. Sean Wang (NU) for analysis of particle behavior in x-ray images, Dr. Dieter Isheim (NU) for assistance with atom probe tomography, and Ms. Elise Goldfine (NU) for assistance with characterization of x-ray diffraction patterns. This research received funding from the US Army Research Laboratory (award W911NF-19-2-0092 ) and from the Argonne National Laboratory (ANL) via a Laboratory Directed Research and Development (LDRD) project with Dr. Jon Almer. JAG was supported by the Army Research Laboratory (ARL) Oak Ridge Associated Universities (ORAU) via a Journeyman Fellowship grant. This work made use of the EPIC facility of Northwestern University’s NUANCE Center and the Northwestern University Center for Atom-Probe Tomography (NUCAPT) , which have received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource ( NSF ECCS-1542205 ); the MRSEC program ( NSF DMR-1720139 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN) ; the Keck Foundation ; and the State of Illinois , through the IIN. The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI ( DMR-0420532 ) and ONR-DURIP ( N00014-0400798 , N00014-0610539 , N00014-0910781 , N00014-1712870 ) programs. This work also made use of the Materials Characterization and Imaging Facility which receives support from the MRSEC Program ( NSF DMR-1720139 ) of the Materials Research Center at Northwestern University . The authors thank Dr. Jon-Erik Mogonye (U.S. Army Research Laboratory, Adelphi) for numerous useful discussions, Dr. Binna Song (NU), Ms. Kristen Scotti (NU), Mr. Sean Wang (NU), Dr. Andrew Chuang (ANL), Dr. Niranjan Parab (ANL), and Dr. Cang Zhao (ANL) for assistance with in situ imaging experiments, Mr. Sean Wang (NU) for analysis of particle behavior in x-ray images, Dr. Dieter Isheim (NU) for assistance with atom probe tomography, and Ms. Elise Goldfine (NU) for assistance with characterization of x-ray diffraction patterns.

Keywords

  • Additive manufacturing
  • Aluminum
  • Elemental blends
  • In situ diffraction
  • Selective laser melting

ASJC Scopus subject areas

  • Biomedical Engineering
  • General Materials Science
  • Engineering (miscellaneous)
  • Industrial and Manufacturing Engineering

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