Research report: History of the development of FeNiMnAl(Cr) multiprincipal component alloys

A review of research conducted at Dartmouth College traces the development of FeNiMnAl(Cr) multiprincipal-component alloys from 2003 onward, showing how changes in aluminum content, chromium addition and carbon content produced distinct combinations of strength, ductility and environmental performance. The program began with equiatomic and near-equiatomic FeNiMnAl alloys that were nanostructured and two-phase, with B2/body-centered-cubic or B2/L21 structures. These materials appeared to form through spinodal decomposition.

They reached yield strengths as high as 2.35 GPa, but they were brittle. The review also describes the progression toward coarser eutectoid or eutectic B2/face-centered-cubic alloys with lower aluminum contents, and later toward alloys designed to address environmental embrittlement and applications involving concentrated solar power. Lowering the aluminum content produced eutectoid or eutectic two-phase alloys with coarser microstructures.

Eutectic alloys appeared at aluminum contents below 15 at. % and had lower yield strengths, no greater than 800 MPa, but exhibited significant tensile elongation of up to 18%. Chromium was then added at 6 at. % to ameliorate environmental embrittlement; this development led to the first eutectic high-entropy alloy in 2013. The review reports that reducing aluminum below 12 at. % eventually produced single-phase face-centered-cubic alloys, at least in the as-cast state.

These alloys had much lower yield strengths than the early nanostructured materials but reached elongations of up to 50%. Interstitial strengthening by carbon changed this balance: in the single-phase alloys, carbon addition significantly increased yield strength while also increasing ductility. The review presents these as measured results within the investigated alloy series and does not establish that the same combination applies to every composition or processing route.

The review covers mechanical properties measured from 4.2 to 1023 K, together with aqueous corrosion and wear behavior. A higher-chromium multiphase composition, Fe40.2Ni11.3Mn30Al7.5Cr11, was produced with a room-temperature yield strength of 593 MPa and 22% elongation. The materials were also examined in connection with concentrated solar power applications, where the review discusses creep properties, optical absorption and high-temperature corrosion behavior in salts.

Because the supplied article is a review and the accessible source provides only an abstract and preview, the detailed test conditions and results for these measurements are not available here. Across the reported development sequence, the alloy series moves from very strong but brittle nanostructured two-phase materials to less aluminum-rich alloys with greater tensile elongation, then to chromium-containing compositions and carbon-strengthened single-phase alloys. The later multiphase alloy illustrates a further attempt to balance mechanical performance with the environmental and application requirements.

The evidence supports a history of composition and structure being adjusted to address specific measured limitations: brittleness accompanied the highest early strengths, environmental embrittlement motivated chromium addition, and carbon strengthened the single-phase alloys while increasing their ductility. It does not show that one composition is universally optimal, nor does it provide evidence about performance outside the tested temperatures, corrosion media, wear conditions or concentrated-solar-power applications described in the review.

Subject of Research: Historical development and measured properties of FeNiMnAl(Cr) multiprincipal-component alloys

Article Title: History of the development of FeNiMnAl(Cr) multiprincipal component alloys

Article References: Baker, I. (2026). History of the development of FeNiMnAl(Cr) multiprincipal component alloys. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13540-y

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13540-y

Keywords: FeNiMnAl alloys, multiprincipal-component alloys, high-entropy alloys, Dartmouth College, chromium addition, carbon strengthening, spinodal decomposition, corrosion behavior, wear behavior, concentrated solar power, History, development