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The brittle-to-ductile transition in cold-rolled tungsten sheets: On the loss of room-temperature ductility after annealing and the phenomenon of 45° embrittlement

Bonnekoh, Carsten; Lied, Philipp; Pantleon, Wolfgang; Karcher, Thomas; Leiste, Harald; Hoffmann, Andreas; Reiser, Jens; Rieth, Michael

Abstract:
The high brittle-to-ductile transition (BDT) temperature of conventionally produced tungsten (W), challenges the design of W-based structural components. Recent studies have demonstrated the potential of cold rolling to produce W sheets, which are ductile at room temperature and exhibit a BDT temperature of 208 K. In order to assess the thermal stability of these materials, we conducted isothermal heat treatments (at 1300 K, for annealing durations between 0.1 h and 210 h) combined with studies on the evolution of mechanical properties and microstructure of a severely deformed undoped W sheet. With this work, we demonstrate the need for a stabilized microstructure before utilization of cold-rolled W in high-temperature applications can take place successfully. After annealing at 1300 K for 6 h, the material properties changed remarkably: The BDT temperature increases from 208 K to 473 K and the sharp BDT of the as-rolled condition transforms into a wide transition regime spanning over more than 200 K. This means in fact, an endangered structural integrity at room temperature. We also address the so-called phenomenon of 45° embrittlement of W sheets. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000123503
Veröffentlicht am 11.09.2020
Originalveröffentlichung
DOI: 10.1016/j.ijrmhm.2020.105347
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Angewandte Werkstoffphysik (IAM-AWP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 0263-4368, 0958-0611, 2213-3917
KITopen-ID: 1000123503
Erschienen in International journal of refractory metals & hard materials
Band 93
Seiten Art.-Nr.: 105347
Schlagwörter Isothermal heat treatment; Recovery; Softening kinetics; Apparent activation volume; Annealing texture
Nachgewiesen in Scopus
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