Mechanical and corrosive properties of aluminum-based intermetallics

Keywords

aluminum intermetallics, mechanical, corrosive properties.

Cite as

Shcherbakova L. G., Milman Yu. V., Iefimov M. A., Kuprin V. V., Lukyanov A. I., Chugunova S. I., and Goncharova I. V. Mechanical and corrosive properties of aluminum-based intermetallics. Physicochemical Mechanics of Materials. 2022. 58(1), 022-028.

Abstract

The Al₃Sc, Al₃Zr, Al₃Hf, Al₃V intermetallic compounds used for strengthening of alumi­num alloys were selected for the study. The technology of rapid crystallization from the liquid state developed by the authors for producing amorphous alloys was used for inter­metallics production. Using this technology it is possible to obtain sufficiently fine grains for the as-cast materials in a molten state with a size of 15–20 mm. X-ray analysis showed that the Al₃Zr intermetallic was a single-phase material, and the Al₃Sc, Al₃Hf, Al₃V inter­metallic compound contains several phases. Studies of the mechanical characteristics by indentation showed that the Al₃Hf compound had the maximum hardness HV of 6.75 GPa and yield strength s_SH = 4.86 GPa and the Al₃Sc – the minimal hardness of 2.0 GPa and yield strength σ_SH = 0.86 GPa and this material phase was the most plastic: δ_H = 0.88. It was found that in a 3% NaCl solution the corrosion potentials (E_corr) of Al₃Sc, Al₃Hf and Al₃V compounds had close values (–0.52 – –0.57 V). In the field of potentials close to E_corr the dissolution rate of intermetallic phases in a 3% NaCl solution increase in the sequence: Al₃Sc < Al₃Hf < Al₃V. The role of the intermetallic phase in the process of corrosion dissolution of the aluminum alloy depends on its composition, which determines the value of E_corr in this aggressive environment. It is shown that the anodic dissolution of the Al – 3 mass%. Mg alloy alloyed with 0.3 mass%. Sc in the 3% NaCl solution proceeds in the potential region more negative than the dissolution of the Al₃Sc intermetallic. Thus, the intermetallic phases are cathodic inclusions relative to the Al–Mg alloy matrix and will not selectively dissolve from the alloy under corrosion conditions.

References

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