J. Mater. Sci. Technol. ›› 2021, Vol. 87: 196-206.DOI: 10.1016/j.jmst.2021.01.055

• Research Article • Previous Articles     Next Articles

Joint effect of quasicrystalline icosahedral and L12-strucutred phases precipitation on the grain structure and mechanical properties of aluminum-based alloys

A.G. Mochugovskiya, N. Yu. Tabachkovaa,b, M. Esmaeili Ghayoumabadia, V.V. Cheverikina, A.V. Mikhaylovskayaa,*()   

  1. aNational University of Sciences and Technology “MISIS”, 119049, Leninskiy Ave. 4, Moscow, Russia
    bProkhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
  • Received:2020-10-20 Revised:2021-01-09 Accepted:2021-01-11 Published:2021-10-10 Online:2021-03-17
  • Contact: A.V. Mikhaylovskaya
  • About author:* E-mail address: mihaylovskaya@misis.ru (A.V. Mikhaylovskaya).

Abstract:

Dispersoid hardening is a key factor in increasing the recrystallization resistance and mechanical strength of non-heat treatable aluminum-based alloys. Mn and Zr are the main elements that form dispersoids in commercial Al-based alloys. In this work, the annealing-induced precipitation behavior, the grain structure, and the mechanical properties of Al-3.0Mg-1.1 Mn and Al-3.0Mg-1.1 Mn-0.25 Zr alloys were studied. The microstructure and the mechanical properties were significantly affected by annealing regimes after casting for both alloys. The research demonstrated a possibility to form high-density distributed quasicrystalline-structured I-phase precipitates with a mean size of 29 nm during low-temperature annealing of as-cast alloys. Fine manganese-bearing precipitates of I-phase increased recrystallization resistance and significantly enhanced the mechanical strength of the alloys studied. The estimated strengthening effect owing to I-phase precipitation was 150 MPa. Due to the formation of L12-structured Al3Zr dispersoids with a mean size of 5.7 nm, additional alloying with Zr increased yield strength by about 90 MPa. The L12-phase strengthening effect was estimated through the dislocation bypass looping and shearing mechanisms.

Key words: Aluminum alloy, Quasicrystals, Dispersoid hardening, Recrystallization, Mechanical properties