Mechanical and Corrosion Properties of Intermetallics Based on Aluminum

We study Al 3 Sc, Al 3 Zr, Al 3 Hf, and Al 3 V intermetallic compounds playing the role of hardening phase in aluminum alloys. We use the technology of rapid crystallization from the liquid state. We obtain relatively fine grains d ∼ 15 μm in size for cast materials. By the method of X-ray diffracti...

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Bibliographic Details
Published in:	Materials science (New York, N.Y.) Vol. 58; no. 1; pp. 20 - 27
Main Authors:	Shcherbakova, L. G., Milman, Yu. V., Iefimov, М. A., Kuprin, V. V., Lukyanov, A. І., Chugunova, S. І., Goncharova, І. V.
Format:	Journal Article
Language:	English
Published:	New York Springer US 01-07-2022 Springer Springer Nature B.V
Subjects:	Alloys Aluminum Aluminum alloys Aluminum base alloys Analysis Anodic dissolution Characterization and Evaluation of Materials Chemical composition Chemistry and Materials Science Corrosion Corrosion and anti-corrosives Crystallization Diffraction Dissolution Hardness Inclusions Indentation Intermetallic compounds Intermetallic phases Magnesium Materials Science Mechanical properties Sodium chloride Solid Mechanics Structural Materials X-rays Yield stress mechanical and corrosive properties aluminum intermetallics
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Summary:	We study Al 3 Sc, Al 3 Zr, Al 3 Hf, and Al 3 V intermetallic compounds playing the role of hardening phase in aluminum alloys. We use the technology of rapid crystallization from the liquid state. We obtain relatively fine grains d ∼ 15 μm in size for cast materials. By the method of X-ray diffraction analysis, it is shown that the Al 3 Zr intermetallic compound is a single-phase material, whereas the Al 3 Sc, Al 3 Hf, and Al 3 V intermetallics consist of several phases. The investigation of the mechanical characteristics by the indentation method shows that the Al 3 Hf intermetallic has the maximum hardness HV = 6.75 GPa and the maximum yield stress σ SH = 4.86 GPa, whereas the Al 3 Sc intermetallic has the minimum hardness HV = 2.0 GPa, the minimum yield strength σ SH = 0.86 GPa and the most plastic phase δ H = 0.88. It is established that, in a 3% NaCl solution, the corrosion potentials ( E corr ) of the Al 3 Sc, Al 3 Hf, and Al 3 V compounds have close values ((– 0.52)–(– 0.57) V). In the potential range close to E corr , the dissolution rate of intermetallic phases in a 3% NaCl solution increases in the following order: Al 3 Sc < Al 3 Hf < Al 3 V. The role of intermetallic phase in the process of corrosion dissolution of aluminum alloy depends on its chemical composition, which determines the value of E corr in aggressive media. We prove that the anodic dissolution of an Al–3 wt.% Mg alloy doped with 0.3 wt.%. Sc in a 3% NaCl solution runs within the potential range more negative than the dissolution potential of the Al 3 Sc intermetallic compound. Thus, the intermetallic phases are cathodic inclusions relative to the matrix of the Al–Mg alloy that do not selectively dissolve under the corrosion conditions.
ISSN:	1068-820X 1573-885X
DOI:	10.1007/s11003-022-00625-7