Impurity control to enhance mechanical properties of severely deformed tungsten
Keckes JF, Jabr A, Wurmshuber M, Bermejo R, Kiener D (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 139
Article Number: 107819
DOI: 10.1016/j.ijrmhm.2026.107819
Abstract
Tungsten is a prime candidate material for plasma-facing components in fusion reactors due to its exceptional high-temperature properties, but its performance is limited by brittleness and sensitivity to impurities. This study investigates the influence of impurities on the mechanical properties of ultrafine-grained tungsten processed by High-Pressure Torsion (HPT). Five tungsten samples with varying impurity contents were produced through different processing routes: vacuum sintering, hydrogen atmosphere sintering, spark plasma sintering (SPS), as well as as-received ultra-high purity (UHP) tungsten. All samples were subsequently deformed by HPT to achieve comparable microstructures with median grain sizes between ∼100 and 160 nm. Secondary-ion mass spectrometry revealed significant variations of oxygen, fluorine, sulfur, phosphorus and chlorine ion intensities. Micromechanical characterization using in situ microcantilever bending showed significant property variations despite similar microstructures. UHP tungsten and hydrogen-sintered tungsten exhibited the highest strength, while vacuum-sintered material showed the lowest. Conversely, SPS-processed tungsten demonstrated superior ductility, paired with intermediate strength. All specimens fractured in intergranular mode, confirming that grain boundary properties govern mechanical behavior in this grain size regime. Furthermore, intentional oxygen exposure of powder prior to SPS-processing did not significantly reduce strength or ductility compared to the non-exposed variant, demonstrating the higher impact of processing parameters on final material properties. The distribution of impurities across a larger grain boundary area is identified to be key in mitigating some embrittling effects commonly observed in coarse-grained tungsten. These findings provide crucial insights for tailoring tungsten processing routes to achieve improved combinations of strength and ductility for extreme operating conditions.
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Austria (AT)How to cite
APA:
Keckes, J.F., Jabr, A., Wurmshuber, M., Bermejo, R., & Kiener, D. (2026). Impurity control to enhance mechanical properties of severely deformed tungsten. International Journal of Refractory Metals & Hard Materials, 139. https://doi.org/10.1016/j.ijrmhm.2026.107819
MLA:
Keckes, J. F., et al. "Impurity control to enhance mechanical properties of severely deformed tungsten." International Journal of Refractory Metals & Hard Materials 139 (2026).
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