Iron-Based High-Temperature Alloys: Alloying Strategies and New Opportunities

Abstract

Iron-based high-temperature alloys are engineered to withstand extreme conditions, including elevated temperatures, mechanical stress, and corrosive environments. These alloys play a critical role in industries such as aerospace, power generation, and chemical processing, where materials must maintain structural integrity and performance under demanding operational conditions. This review examines recent advancements in iron-based alloys, with a focus on alloying strategies, high-temperature performance, and applications. Traditional approaches-including alloy design, microstructure control, process optimization, and computational modeling-continue to enhance alloy performance. Furthermore, emerging technologies such as high-entropy alloy (HEA) design, additive manufacturing (AM), nanostructured design with nanophase strengthening, and machine learning/artificial intelligence (ML/AI) are revolutionizing the development of iron-based superalloys, creating new opportunities for advanced material applications.

Keywords: Fe-based alloy; additive manufacturing; alloying strategy; high-entropy alloy; high-temperature application.

Figure 6

(A) Various protective films ((a,b) Cr-rich spinel or hematite films, (c) Al₂O₃ film) formed on the surfaces of FeCrAl alloys in various environments: (a,b) in low- and high-oxygen-activity aqueous environments, (c) under HT steam oxidation (1200 °C, 4 h), Reprinted with permission from Ref. [85] Copyright © 2018 Elsevier. (B) Surface morphology of the HEA alloys after the isothermal oxidation test for 20 h, Reprinted with permission from Ref. [257] Copyright © 2021 Elsevier. (C) Schematic illustration of the surface steam oxidation mechanism in an Fe–Cr–Al alloy, Reprinted with permission from Ref. [87]. Copyright © 2022 Elsevier (D) Hybrid molecular dynamics and Monte Carlo simulations of atomic migration behavior in the Al-depletion layer for FeCrAl alloy (a,b), NiCoCrAl alloy (c,d), and AlCoCrFeNi HEA (e,f) at 1100 °C, Reprinted with permission from Ref. [244] Copyright © 2022 Elsevier.

Figure 9

(A,a) DSC curves for the Fe_84.75Si₂B₉P₃C_0.5Cu_0.75 alloy before (as-quenched) and after annealing at 420 °C for different times (1–96 min). (A,b) Average grain size (symbols represent the experimental data from XRD and lines are the proposed modeling curves, while the inset is the proposed “dual phase co-growth model”) of the Fe-based nanocrystalline alloys during isothermal annealing at 420 and 460 °C. (B,a,b) APT elemental maps (60 × 60 × 110 nm) of the Fe-based nanocrystalline alloy after annealing at 420 °C for 48 min. (c) Concentration depth profile from the selected area (3 × 3 × 60 nm) in (B,a). (B,d,e) Fe and Cu, respectively, delineated by 90 at.% and 4 at.% iso-concentration surfaces, Reprinted with permission from Ref. [300] Copyright © 2019 Elsevier. (C) Three typical structures (monolith, foam, and fiber) of FeCrAl alloys as catalytic supports, Reprinted with permission from Ref. [24] Copyright © 2020 American Chemical Society. (D) Schematic illustration of the preparation and proposed PMS activation mechanism of FeSiB amorphous alloys for dye degradation, Reprinted with permission from Ref. [315] Copyright © 2017 Elsevier.

Figure 1

(a) Typical classification of HTAs. (b) Main materials used for the Trent 800 engine manufacturing. Reprinted with permission from Ref. [18]. Copyright 2023, Springer Nature (c,d) The trend in the number of publications (last 20 years) and variation in the keywords burst detection analysis (last 10 years) from VOSviewer 1.6.20 as part of the topic “Iron-based alloys” from Web of science.

Figure 2

(a) Typical five alloying elements used in Fe-based alloys and their effects on mechanical performance, Reprinted from Ref. [66], Open access. (b) Application of AI and ML techniques in steels, reprinted from Ref. [72], Copyright © 2023, Springer Nature. (c) Schematic diagram of a prediction model for Fe–C alloys based on the backpropagation neural network model, Reprinted from Ref. [66], Open access.

Figure 3

(a) Schematic diagram of the various developmental stages of metal-based materials according to configurational entropy. Reprinted with permission from Ref. [113]. Copyright © 2025, Springer Nature. Schematic diagram of the controllable synthesis strategy (b) Reprinted with permission from Ref. [115] Copyright © 2024, The Royal Society of Chemistry. Four core effects of HEAs (c) Reprinted with permission from Ref. [116] Copyright © 2024, Springer Nature. (EHEAs = eutectic high-entropy alloys, RHEAs = refractory high-entropy alloys, HESAs = high-entropy superalloys).

Figure 4

(a) A schematic diagram of alloy design for metal additive manufacturing, Reprinted with permission from Ref. [164] Copyright © 2018 John Wiley and Sons. (b) A comparison of properties obtained by conventional processing and by the two 3D-printed processes (DED and L-PBF) (the kind of steel is denoted by field color, while the field border indicates the method of production), Reprinted with permission from Ref. [169] Copyright © 2019 Elsevier. (c) Mechanical properties of 3D-printed 1080 (left) and 1040 (right) steels in comparison with their conventionally wrought counterparts, Reprinted with permission from Ref. [170] Open access. (CET = Columnar to equiaxed transition, L-PBF = laser powder-bed fusion, ODS = oxide dispersion-strengthened, C-tool steels = carbon-bearing tool steels, PH = precipitation hardening).

Figure 5

Schematic diagram of composition design via machine learning for Fe–Cr–Ni–Al/Ti multi-principal element alloys, Reprinted with permission from Ref. [97] Copyright © 2019 Elsevier.

Figure 7

(A) Sketch of formation process for corrosion layer: (a) the initial stage of corrosion and (b) stable corrosion stage, Reprinted with permission from Ref. [253] Open access. (M = Fe, Cr, Ni, and Al). (B) Fe-base oxygen evolution electrode in molten LiCl–Li₂O at 650 °C—(a) optical photos of the Fe-36Ni anode before (left) and after pre-oxidation (right), (b) XRD data of the oxide scale, optical micrograph (c) and EPMA mapping (d) of the cross-section of the oxide scale ((d1) Fe, (d2) Ni, and (d3) O) , Reprinted with permission from Ref. [256] Open access.

Figure 8

Friction coefficient (a), wear rate (b), and hardness (c) of Fe-based high-entropy alloy and 40Mn18Cr3 steel at different temperatures (RT-800 °C). (d) A schematic illustration of the wear mechanisms of Fe₅₀Mn₂₅Cr₅Al₁₅Ti₅ alloy at different temperatures, Reprinted with permission from Ref. [264] Copyright © 2025 Elsevier.