Ambient- and elevated temperature properties of Sc- and Zr-modified Al–6Ni alloys strengthened by Al3Ni microfibers and Al3(Sc,Zr) nanoprecipitates

C. Suwanpreecha, J. U. Rakhmonov, S. Chankitmunkong, P. Pandee, D. C. Dunand, C. Limmaneevichitr*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The eutectic Al–6Ni (wt.%) alloy exhibits excellent strength at ambient and elevated temperature, provided by a high volume fraction of Al3Ni microfibers formed during solidification. Here, Al–6Ni is micro-alloyed with Sc and Zr (with 0.1Sc+0.2Zr, 0.2Sc+0.4Zr and 0.3Sc+0.2Zr, wt.%), creating two additional populations of primary and secondary Al3(Sc,Zr) precipitates. The fully eutectic microstructure (α-Al + Al3Ni) observed in Al–6Ni alloy changes, with Sc and Zr addition to hypoeutectic microstructure with primary α-Al grains nucleated on solidification by primary Al3(Sc,Zr) precipitates. Upon subsequent aging, fully-coherent Al3(Sc,Zr) nanoprecipitates form in the α-Al matrix between Al3Ni microfibers, providing substantial precipitation strengthening, which is maintained for up to 1 month at 350 °C. Alloy strength - both at ambient temperature and during creep at 300 °C - can be quantitatively described through a superposition of precipitation strengthening by Al3(Sc,Zr) nanoprecipitates and load-transfer strengthening by Al3Ni microfibers.

Original languageEnglish (US)
Article number142963
JournalMaterials Science and Engineering A
Volume841
DOIs
StatePublished - Apr 28 2022

Keywords

  • Aging
  • Al-Ni-Sc-Zr
  • Aluminum alloys
  • Creep
  • Eutectic strengthening
  • Load transfer
  • Precipitation hardening

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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