From unlikely pairings to functional nanocomposites: FeTi–Cu as a model system
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In: Materials today advances, Vol. 2023, No. 20, 100433, 17.10.2023.
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TY - JOUR
T1 - From unlikely pairings to functional nanocomposites
T2 - FeTi–Cu as a model system
AU - Schweiger, Lukas
AU - Kiener, Daniel
AU - Burtscher, Michael
AU - Schafler, Erhard
AU - Mori, Gregor Karl
AU - Spieckermann, Florian
AU - Eckert, Jürgen
N1 - Publisher Copyright: © 2023 The Authors
PY - 2023/10/17
Y1 - 2023/10/17
N2 - In order to develop materials for energy storage, a bulk nanocomposite with a composition of FeTi-25 vol% Cu was prepared by high-pressure torsion, with FeTi as functional phase for hydrogen storage and Cu as ductile phase to improve the processability. Despite the use of such a highly ductile auxiliary phase, the processability remained challenging due to strain localization in the softer Cu. This behavior is most pronounced at room temperature, and no nanocomposites were formed. At elevated temperatures, the strong strain rate sensitivity of the flow stress of the nanocrystalline Cu facilitates the formation of a FeTi–Cu nanocomposite due to a self-reinforcing process. Nevertheless, fragmentation of FeTi is limited because the resulting massive strain hardening prevents controlled processing at temperatures <250 °C, and Cu-rich shear bands develop at temperatures >250 °C. Satisfactory microstructural homogeneity is only achieved at the highest deformation temperatures of 550 °C. Overall, this study highlights that for unlikely material pairings, as often required in the pursuit of superior functional materials, the mechanical behavior of the phases involved and their interplay remains critical and must be thoroughly investigated when aiming for controlled structural homogeneity of bulk nanomaterials.
AB - In order to develop materials for energy storage, a bulk nanocomposite with a composition of FeTi-25 vol% Cu was prepared by high-pressure torsion, with FeTi as functional phase for hydrogen storage and Cu as ductile phase to improve the processability. Despite the use of such a highly ductile auxiliary phase, the processability remained challenging due to strain localization in the softer Cu. This behavior is most pronounced at room temperature, and no nanocomposites were formed. At elevated temperatures, the strong strain rate sensitivity of the flow stress of the nanocrystalline Cu facilitates the formation of a FeTi–Cu nanocomposite due to a self-reinforcing process. Nevertheless, fragmentation of FeTi is limited because the resulting massive strain hardening prevents controlled processing at temperatures <250 °C, and Cu-rich shear bands develop at temperatures >250 °C. Satisfactory microstructural homogeneity is only achieved at the highest deformation temperatures of 550 °C. Overall, this study highlights that for unlikely material pairings, as often required in the pursuit of superior functional materials, the mechanical behavior of the phases involved and their interplay remains critical and must be thoroughly investigated when aiming for controlled structural homogeneity of bulk nanomaterials.
UR - http://www.scopus.com/inward/record.url?scp=85174186120&partnerID=8YFLogxK
U2 - 10.1016/j.mtadv.2023.100433
DO - 10.1016/j.mtadv.2023.100433
M3 - Article
VL - 2023
JO - Materials today advances
JF - Materials today advances
SN - 2590-0498
IS - 20
M1 - 100433
ER -