Atomic-scale pathway of early-stage precipitation in Al–Mg–Si alloys Academic Article uri icon

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abstract

  • Strengthening in age-hardenable alloys is mainly achieved through nano-scale precipitates whose formation paths from the atomic-scale, solute-enriched entities are rarely analyzed and understood in a directly-verifiable way. Here, we discover a pathway for the earliest-stage precipitation in Al-Mg-Si alloys: solute clustering leading to three successive variants of FCC clusters, followed by the formation of non-FCC $GP$-$zones$. The clusters, which originally assume a spherical morphology ($C1$), evolve into elongated clusters and orient themselves on $\{111\}_{Al}$ ($C2$) and subsequently on $\{100\}_{Al}$ planes and $<$$100$$>_{Al}$ directions ($C3$). We also analyze the association of quenched-in dislocations with clustering phenomena. The results of this work can open a new frontier in advancing alloy-process-property design for commercially-important age-hardenable Al alloys.

authors

  • Fallah, Vahid
  • Korinek, Andreas
  • Ofori-Opoku, Nana
  • Raeisinia, Babak
  • Gallerneault, Mark
  • Provatas, Nikolas
  • Esmaeili, Shahrzad

publication date

  • January 2015