A state-of-the-art review in metal additive manufacturing of medium entropy alloys: Recent trends and future perspectives

Omonini Clifford, Adel Almasbek, Akniyet Toktamys, Andrei Yankin, Didier Talamona, Asma Perveen

International Journal of Lightweight Materials and Manufacture, 2026

Full text Open access: Gold Metadata (CSL-JSON)
DOI 10.1016/j.ijlmm.2026.06.006
Data confidence 85 high
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Abstract

Medium-entropy alloys (MEAs), characterized by configurational entropy in the range of 1.0 R <Δ S conf ≤1.5 R , represent a thermodynamically distinct space between traditional alloys and high-entropy alloys. With fewer constituent elements, MEAs offer simpler phase analysis and clearer mechanistic insights compared to more complex systems. At the same time, their entropy-stabilized structures remain highly responsive to thermal processing, making them especially compatible with additive manufacturing (AM) techniques. This review draws on over 200 studies from the last ten years, concentrating on laser powder bed fusion (LPBF) processing of CoCrNi-based systems (including CoNiV and CoNiTa) and refractory compositions (NbTiZr, NbTiTa). Other methods, such as directed energy deposition (DED), are addressed as complementary routes. The intense thermal gradients and fast cooling rates typical of AM foster complex, layered microstructures that promote twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP), resulting in superior strength and ductility compared to their cast counterparts. These enhanced properties are driving interest in structural components, soft-magnetic devices, cryogenic equipment, corrosion-resistant materials, and biomedical implants. The paper also examines progress in computational methods, including CALPHAD-based thermodynamic modelling, first-principles predictions of stacking fault energy, and machine learning for process refinement. However, model reliability remains limited by sparse training data. Key challenges persist, such as inconsistent documentation of processing parameters, vulnerability to defects in refractory compositions, and a lack of long-term performance and biocompatibility assessments. To accelerate the adoption of AM-fabricated MEAs, the development of standardized reporting practices and broader access to shared alloy databases is deemed essential.