Precipitation behavior of L12 Al3Zr phase in Al-Mg-Zr alloy

Journal Article · Tue May 15 04:00:00 EDT 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.02.030· OSTI ID:22804964

Mochugovskiy, A. G.; Levchenko, V. S.; Tabachkova, N. Yu.; Mufalo, W.; Portnoy, V. K. ^[1]

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1. National University of Science and Technology “MISiS”, 4, Leninsky Prospekt, Moscow 119049 (Russian Federation)

Highlights: • Precipitation behavior of the as-cast Al-3.0Mg-0.25Zr alloy was studied. • Discontinuous and continuous precipitation mechanisms of Al{sub 3}Zr phase are observed. • Precipitation type changes from discontinuous to continuous at two-step annealing. • Developed treatment mode provides high dispersoids dense and maximum aging effect. - Abstract: Increasing the recrystallization resistance and the mechanical properties of aluminum-based alloys is possible due to the formation of a nanoscale L1{sub 2}-structured Al{sub 3}Zr phase. Treatment conditions and alloys composition affect the size and density of dispersoids and their final properties. In this work we analyze the decomposition of the supersaturated solid solution in the as-cast Al-3%Mg-0.25%Zr alloy for different annealing modes to understand the precipitation kinetics of the Al{sub 3}Zr phase in the presence of Mg. We found that both discontinuous and continuous precipitation mechanisms of the Al{sub 3}Zr phase are possible in the studied low-alloyed material. One-step annealing leads to the formation of coarse (17 nm) spherical precipitates of a coherent L1{sub 2}-structured Al{sub 3}Zr phase and discontinuously formed fan-shaped aggregations of the same phase. Two-step annealing provided for the maximum precipitation hardening with the formation of high-density nanoscale (7 nm) dispersoids of the Al{sub 3}Zr phase. This study highlights the importance of the annealing mode of the as-cast material for achieving a high density of the fine L1{sub 2} structured Al{sub 3}Zr phase and the maximum hardening effect.

• OSTI ID: 22804964
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 139; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
ANNEALING
AUGMENTATION
DECOMPOSITION
MAGNESIUM COMPOUNDS
NANOSTRUCTURES
PRECIPITATION HARDENING
RECRYSTALLIZATION
SOLID SOLUTIONS
TERNARY ALLOY SYSTEMS
ZIRCONIUM COMPOUNDS