In-house synthesis of CoCrFeNi ingots using an electric furnace

Colombini, Elena; Gualtieri, Magdalena Lassinantti; Mortalò, Cecilia; Deambrosis, Silvia Maria; Veronesi, Paolo

doi:10.1016/j.matlet.2022.132571

Cited by 2 publications

(11 citation statements)

References 17 publications

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“…Sample Preparation: The equimolar CoCrFeNi bulk alloy investigated in this work was obtained by melting a prealloyed powder followed by solidification during natural cooling in an electric furnace with Ar atmosphere, as described in a recent work. [12] Although structurally homogeneous (fcc), the typical dendritic-interdendritic microstructure of the bulk shows segregation of Cr and Co in the interdendritic region. [12] The bulk alloy was cut using a low-speed cutting machine (Micromet, Remet, Bologna, Italy) equipped with an abrasive disk made of alumina embedded in resin (Struers).…”

Section: Methodsmentioning

confidence: 99%

“…[12] Although structurally homogeneous (fcc), the typical dendritic-interdendritic microstructure of the bulk shows segregation of Cr and Co in the interdendritic region. [12] The bulk alloy was cut using a low-speed cutting machine (Micromet, Remet, Bologna, Italy) equipped with an abrasive disk made of alumina embedded in resin (Struers). An aqueous cutting fluid containing a lubricant was used during the operation.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, continuous stiffness measurements (CSM) and quasi-static nanoindentations as well as microindentations were also performed. The sample, extensively investigated in a previous work, [12] is structurally homogeneous (fcc) but exhibits a typical dendritic-interdendritic microstructure with segregation of Cr in the interdendritic region. As solid solution strengthening in HEAs can lead to remarkable increases in hardness and is strongly dependent on the chemical composition, [20,21,33] it was hypothesized that the observed microsegregation would be reflected in high-throughput nanohardness maps and that statistical elaboration of the measurement output would be useful in determining the individual mechanical properties of the specific phases.…”

Section: Doi: 101002/adem202300110mentioning

confidence: 99%

“…The equimolar bulk FeNiCrCo alloy investigated in this work was synthesized by melting of prealloyed powders followed by natural cooling (see ref. [12] for further details). The resulting sample exhibits a dendritic-interdendritic microstructure with the interdendritic region being enriched in Cr and depleted in Co and Fe.…”

Section: High-speed Nanoindentation On a Chemically-mechanically Poli...mentioning

confidence: 99%

“…[10] The as-cast CoCrFeNi alloy is known to crystallize in an fcc structure, sometimes reported to have a certain degree of microsegregation with Cr accumulated in the grain boundaries. [11,12] Accelerated cooling from the melted state may even lead to the crystallization of a Cr-rich bcc phase in the interdendritic region that leads to an overall increase in microhardness. [11] The cooling-rate dependence of microstructure and mechanical properties of as-cast HEAs has been investigated in more detail by others.…”

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confidence: 99%

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High‐Throughput Nanoindentation Mapping of a Microsegregated CoCrFeNi Multi‐Principal Element Alloy (MPEA): Challenges and Limitations

et al. 2023

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Equimolar CoCrFeNi is a popular multi‐principal element alloy, generally obtained by melt‐aided routes. The dendritic microstructure of as‐cast alloys is cooling‐rate dependent and thus may show different macromechanical behaviors. Knowledge about the nanomechanics of chemically/structurally distinct zones is important for explaining these differences and facilitating material's design through processing conditions. To this aim, high‐throughput nanoindentation mapping is a potentially powerful tool. However, results are possibly biased by the indentation size effect (ISE) and plastically deformed surfaces induced by inadequate sample preparation. This work is aimed at giving some guidelines for map acquisition and sample preparation based on data from various nanoindentation techniques (i.e., high‐throughput nanoindentation, continuous stiffness, and quasi‐static measurements) collected on differently polished surfaces. It is shown that conventional metallographic preparation leads to a plastically deformed layer that penetrates deep into the surface (11–17 μm). Electropolishing is efficient in removing this layer. However, difficulties may arise due to preferential corrosion in a multiphase system wherefore polishing conditions needs optimization. Nanoindentations of adequately prepared surfaces of CoCrFeNi result in an important ISE, which affects measurements at depths lower than ca 2000 nm. This must be taken into account when performing high‐throughput nanoindentation mapping of this material.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%