Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during isothermal aging at 375-425 °C

Keith E. Knipling*, David C. Dunand, David N. Seidman

*Corresponding author for this work

Research output: Contribution to journalArticle

148 Scopus citations

Abstract

Formation of Al3Zr or Al3(Zr1-x Tix) precipitates with a metastable L12 structure was investigated in conventionally solidified A1-0.1 Zr, Al-0.2 Zr, Al-0.1 Zr-0.1 Ti, and Al-0.2 Zr-0.2 Ti (at.%) alloys aged isothermally at 375, 400, or 425 °C. Pronounced hardening results from nanometer-scale, spheroidal Al3Zr or Al3(Zr1-xTix) (L12) precipitates within solute-enriched dendrites. Interdendritic regions contain a significantly lower number density of coarser cauliflower-, rod- and plate-shaped precipitates with the L12 structure. Neither the magnitude of the peak-aged hardness, nor the subsequent loss in hardness due to overaging, is affected by ternary additions of Ti. After extended aging times (1600 h) at 425 °C, there is no difference in the mean precipitate radii of spheroidal Al3Zr or Al3(Zr1-xTix) precipitates, confirming that Ti additions do not improve the coarsening resistance. Comparison with prior coarsening studies on Al3Zr, and Al3(Zr1-xVx), Al3(Zr1-xTix) and Al3(Zr1-x-yV xTiy) (L12) precipitates at 425 °C confirms the lack of an effect from ternary alloying additions.

Original languageEnglish (US)
Pages (from-to)114-127
Number of pages14
JournalActa Materialia
Volume56
Issue number1
DOIs
StatePublished - Jan 1 2008

Keywords

  • Aluminum alloys
  • Coarsening
  • Precipitation strengthening
  • Titanium
  • Zirconium

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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