Stacking Fault Energy in Metallic Alloys

Stacking fault energy (SFE) is a fundamental parameter governing the formation and mobility of partial dislocations, mechanical twinning and phase transformations in metallic alloys. In face-centred cubic (FCC) systems, variations in SFE dictate whether plasticity is accommodated by extended partial dislocations separated by stable stacking faults or by deformation twins, with lower SFE promoting twinning-induced plasticity and complex defect interactions. In high-entropy alloys (HEAs) and multi-principal element systems, the local chemical environment and short-range order markedly influence the intrinsic stacking fault energy (ISFE), giving rise to compositional tuning of strength and ductility. Thermodynamic contributions from electronic, vibrational and magnetic degrees of freedom render SFE temperature dependent, which in turn affects high-temperature creep resistance and phase stability. Advances in first-principles calculations, machine-learning interatomic potentials and high-resolution microscopy have enabled quantitative mapping of the generalised stacking fault energy (GSFE) landscape across different slip and twin systems. The global significance of SFE research is reflected in its impact on the design of nickel-based superalloys, lightweight aluminium alloys and cryogenic-temperature steels, where precise control of fault energies underpins superior mechanical performance and extended component lifetimes.

Research from Nature Portfolio

Recent developments have delivered machine-learning interatomic potentials that accurately reproduce defect energetics and phase transitions in nickel. A “magnetism-hidden” deep potential model for Ni captures finite-temperature lattice, elastic and defect properties, enabling large-scale simulations of FCC–HCP transformations and associated stacking fault energetics under high stress. First-principles studies on FeNiCoCr high-entropy alloys have elucidated how dilute additions of aluminium enhance twinnability by lowering the intrinsic stacking fault energy, whereas molybdenum predominantly increases fault density without significant twin activation. Seminal first-principles work on hexagonal close-packed gold has characterised the generalised stacking fault and twin-boundary energies in basal and non-basal systems, revealing exceptionally low fault energies that facilitate phase transformation from HCP to FCC and informing strategies for fabricating novel crystal structures.

Stacking Fault Energy in Metallic Alloys publication trend

The graph below shows the total number of articles in stacking fault energy in metallic alloys across all publications each year (not limited to Nature Index journals).

Technical terms

Stacking fault energy (SFE): Energy per unit area required to introduce a fault in the atomic stacking sequence, typically expressed in mJ m^–2.

Generalised stacking fault energy (GSFE): Energy profile mapping unstable and stable configurations as one crystal plane is rigidly displaced over another, revealing critical slip barriers.

Intrinsic stacking fault energy (ISFE): Energy of the stable partial dislocation configuration corresponding to a stacking fault, distinct from the maximum (unstable) fault energy.

Twinning-induced plasticity (TWIP): Deformation mechanism in which mechanical twins form under stress, enhancing work hardening, ductility and energy absorption.

High-entropy alloy (HEA): Alloy containing five or more principal elements in near-equiatomic proportions, yielding high configurational entropy and complex defect behaviour.

References

1. An accurate and transferable machine learning interatomic potential for nickel. Communications Materials (2024).
2. Temperature dependence of the stacking-fault Gibbs energy for Al, Cu, and Ni. Physical Review B (2018).
3. Generalized-stacking-fault energy and twin-boundary energy of hexagonal close-packed Au: A first-principles calculation. Scientific Reports (2015).
4. The influence of dilute aluminum and molybdenum on stacking fault and twin formation in FeNiCoCr-based high entropy alloys based on density functional theory. Scientific Reports (2019).
5. First-principles calculations of intrinsic stacking fault energies and elastic properties in binary nickel alloys. Materialia (2024).
6. Effect of stacking fault energy (SFE) of single crystal, equiatomic CrCoNi and Cantor alloy on creep resistance. Materials Science and Engineering A (2024).