Mechanical Engineering Properties of CMAs

Eckert, J.; Scudino, Sergio; Stoica, M.; Kenzari, Samuel; Sales, Muriel

doi:10.1002/9783527632718.ch7

Cited by 5 publications

(5 citation statements)

References 94 publications

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“…(1) Al-Co alloys (7,10,15,20 wt.% Co) were prepared by vacuum arc remelting. Highly directional microstructures were attained.…”

Section: Discussionmentioning

confidence: 99%

“…Al-Co alloys (7,10,15,20 wt.% Co or 3.3, 4.9, 7.5, 10.3 at.% Co, respectively) were fabricated by vacuum arc remelting (VAR). Appropriate mixtures of Al powder (finer than 44 µm, 99.5% purity) and Co powder (finer than 37 µm, 99.5% purity), were introduced into the furnace (placed in a water cooled copper crucible) and were melted at~(2200-2500)˝C.…”

Section: Raw Materials and Fabricationmentioning

confidence: 99%

See 1 more Smart Citation

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Lekatou

Sfikas

Petsa

et al. 2016

Metals

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Hypereutectic Al-Co alloys of various Co contents (7-20 weight % (wt.%) Co) were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co) to coarse primary Al 9 Co 2 predominance (20 wt.% Co). Co dissolution in Al far exceeded the negligible equilibrium solubility of Co in Al; however, it was hardly uniform. By increasing the cobalt content, the fraction and coarseness of Al 9 Co 2 , the content of Co dissolved in the Al matrix, and the hardness and porosity of the alloy increased. All alloys exhibited similar corrosion behavior in 3.5 wt.% NaCl with high resistance to localized corrosion. Al-7 wt.% Co showed slightly superior corrosion resistance than the other compositions in terms of relatively low corrosion rate, relatively low passivation current density and scarcity of stress corrosion cracking indications. All Al-Co compositions demonstrated substantially higher resistance to localized corrosion than commercially pure Al produced by casting, cold rolling and arc melting. A corrosion mechanism was formulated. Surface films were identified.

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“…(1) Al-Co alloys (7,10,15,20 wt.% Co) were prepared by vacuum arc remelting. Highly directional microstructures were attained.…”

Section: Discussionmentioning

confidence: 99%

Section: Raw Materials and Fabricationmentioning

confidence: 99%

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Lekatou

Sfikas

Petsa

et al. 2016

Metals

View full text Add to dashboard Cite

show abstract

“…Results indicate that a galvanic mechanism is involved. Moreover, it should be mentioned that Al–Co IMCs are brittle [ 85 ]. Therefore, a piling of noble but brittle particles, such as β(AlCo), in pores resulting from massive dissolution of surrounding less-noble phases may significantly influence the alloy stability [ 82 ].…”

Section: Al–co Alloysmentioning

confidence: 99%

“…The parallel occurrence of SCIPs with similar chemical compositions has a positive effect on the corrosion susceptibility of the alloy [ 84 , 85 ]. The Al 74 Co 24 alloy was composed of three phases with close chemical compositions (Z–Al 3 Co, Al 5 Co 2 , and Al 13 Co 4 , [ 84 ]).…”

Section: Al–co Alloysmentioning

confidence: 99%

Aqueous Corrosion of Aluminum-Transition Metal Alloys Composed of Structurally Complex Phases: A Review

et al. 2021

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Complex metallic alloys (CMAs) are materials composed of structurally complex intermetallic phases (SCIPs). The SCIPs consist of large unit cells containing hundreds or even thousands of atoms. Well-defined atomic clusters are found in their structure, typically of icosahedral point group symmetry. In SCIPs, a long-range order is observed. Aluminum-based CMAs contain approximately 70 at.% Al. In this paper, the corrosion behavior of bulk Al-based CMAs is reviewed. The Al–TM alloys (TM = transition metal) have been sorted according to their chemical composition. The alloys tend to passivate because of high Al concentration. The Al–Cr alloys, for example, can form protective passive layers of considerable thickness in different electrolytes. In halide-containing solutions, however, the alloys are prone to pitting corrosion. The electrochemical activity of aluminum-transition metal SCIPs is primarily determined by electrode potential of the alloying element(s). Galvanic microcells form between different SCIPs which may further accelerate the localized corrosion attack. The electrochemical nobility of individual SCIPs increases with increasing concentration of noble elements. The SCIPs with electrochemically active elements tend to dissolve in contact with nobler particles. The SCIPs with noble metals are prone to selective de-alloying (de–aluminification) and their electrochemical activity may change over time as a result of de-alloying. The metal composition of the SCIPs has a primary influence on their corrosion properties. The structural complexity is secondary and becomes important when phases with similar chemical composition, but different crystal structure, come into close physical contact.

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“…The interesting surface properties (associated with a low surface energy) include low wetting by water [15], low solid-solid adhesion [16,17], intriguing features in solid film growth [18]), oxidation resistance [18], corrosion resistance [19], friction anisotropy [20], low friction [16,18].Despite their unusual properties, CMA applications are still in an early stage of maturity. The reason is that being notably brittle, CMAs are regarded unsuitable for applications as monolithic alloys, but still viable as coatings and composites [19]. However, CMAs as coatings present intrinsically poor adherence to their substrates owing to their low surface energy [20]; thus, the use of a bond coat is recommended [21].…”

Section: Introductionmentioning

confidence: 99%

Αl- (Al9 Co2 , Al13Co4 ) Powder Metallurgy Processed Composite Materials: Analysis of Microstructure, Sliding Wear and Aqueous Corrosion

Karantzalis¹

2017

Mater. Sci. Eng. Adv. Res

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The present effort was undertaken in order to investigate the manufacturing of aluminum based composites, reinforced by a dual intermetallic phase, Al 9 Co 2 -Al 13 Co 4 , using a powder metallurgy route. The metal matrix was reinforced with compositions 2, 5 and 10% vol. The manufacturing of the dual Al 9 Co 2 -Al 13 Co 4 powders was carried out by vacuum arc melting followed by milling to produce fine-sized powders. The composite materials were produced by a common powder metallurgy route, including mixing in a mortar, consolidation by cold pressing, and sintering under vacuum at 600°C. The wear properties of the composite were examined by dry sliding wear against an alumina counter face at 10cm/s, a load at 1N and a distance at 1000m. Macro hardness was also assessed. Aqueous corrosion experiments in 3.5% NaCl at 25°C were carried out in all three different compositions. Optical microscopy and SEM-EDX analysis were used in order to ascertain the microstructure, the sliding wear tacks and debris and the corroded surfaces. The sliding wear phenomena were related to the microstructural features and approached based on classic theories of Al composite wear behaviour and so was the corrosion response of the produced materials.

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Mechanical Engineering Properties of CMAs

Cited by 5 publications

References 94 publications

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Aqueous Corrosion of Aluminum-Transition Metal Alloys Composed of Structurally Complex Phases: A Review

Αl- (Al9 Co2 , Al13Co4 ) Powder Metallurgy Processed Composite Materials: Analysis of Microstructure, Sliding Wear and Aqueous Corrosion

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