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As efforts associated with the exploration of multi-principal element alloys (MPEAs) using computational and data-intensive methods continue to rise, experimental realization and validation of the predicted material properties require high-throughput and combinatorial synthesis of these alloys. While additive manufacturing (AM) has emerged as the leading pathway to address these challenges and for rapid prototyping through part fabrication, extensive research on developing and understanding the process-structure-property correlations is imminent. In particular, directed energy deposition (DED) based AM of MPEAs holds great promise because of the boundless compositional variations possible for functionally graded component manufacturing as well as surface cladding. We analyze the recent efforts in DED of MPEAs, the microstructural evolution during the laser metal deposition of various transition and refractory elements, and assess the effects of various processing parameters on the material phase and properties. Our efforts suggest that the development of robust predictive approaches for process parameter selection and modifying the synthesis mechanisms are essential to enable DED platforms to repeatedly produce defect free, stable and designer MPEAs.
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This content will become publicly available on March 1, 2027
Rapid depressurization cooling for single-phase W-based MPEAs
Despite the extensive studies on the fabrication and properties of multi-principal element alloys (MPEAs), particularly with the body-centered cubic (BCC) structure, reliable experimental routes to their single-phase fabrication remain elusive. In this work, we demonstrate a novel processing strategy that enables reproducible synthesis of tungsten-based, single-phase BCC MPEAs. The approach combines spark plasma sintering (SPS), followed by hot isostatic pressing (HIP) and, most crucially, rapid depressurization cooling to low temperatures, which is identified as the key step for suppressing secondary-phase formation. We demonstrate facile single-solid- solution MPEA synthesis across five compositional systems, including three ternary alloys (WTaV, W0.35Ta0.40Cr0.25, and W0.40Ta0.40Ti0.20), a quaternary alloy (W0.40Ta0.40Cr0.10Ti0.10), and a quinary alloy (WTaVCrTi). Using this novel processing route of W0.40Ta0.40Ti0.20 and W0.40Ta0.40Cr0.10Ti0.10 alloys unambiguously facilitated the formation of a solid solution BCC structure, while limiting secondary phases to less than 10 vol%. Additional homogenization heat treatments at 1800 ◦C enhanced compositional homogeneity. Specific measures effectively minimized elemental evaporation during high-temperature processing by encapsulating the sample in tantalum tubes under a pure argon atmosphere and by controlled addition of volatile elements (V and Cr). As a result, dense and homogeneous single-phase BCC alloys (W0.40Ta0.40V0.10Cr0.10, W0.40Ta0.30V0.10Ti0.20, and W0.40Ta0.40V0.05Cr0.05Ti0.10) were successfully produced, enabling accurate calorimetric measurements of formation enthalpies by oxide melt solution calorimetry. This work establishes a reliable experimental processing for producing single-phase W-based MPEAs and provides a foundation for future thermodynamic measurements and database development.
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- Award ID(s):
- 2526634
- PAR ID:
- 10706441
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Journal of Alloys and Compounds
- Volume:
- 1057
- Issue:
- C
- ISSN:
- 0925-8388
- Page Range / eLocation ID:
- 186917
- Subject(s) / Keyword(s):
- Tungsten-based alloys, Single-phase BCC, Processing control, SPS-HIP, Rapid cooling, Phase stability
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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