Journal article
Microcantilever Fracture Tests on Eutectic NiAl-Cr(Mo) In Situ Composites
Publication Details
Authors: | Gabel, S.; Giese, S.; Merle, B.; Sprenger, I.; Heilmaier, M.; Neumeier, S.; Bitzek, E.; Göken, M. |
Publisher: | WILEY-V C H VERLAG GMBH |
Publication year: | 2021 |
Journal: | Advanced Engineering Materials |
Pages range : | 2001464 |
Volume number: | 23 |
Issue number: | 6 |
Number of pages: | 9 |
ISSN: | 1438-1656 |
eISSN: | 1527-2648 |
DOI-Link der Erstveröffentlichung: |
Abstract
Lamellar eutectic NiAl-Cr(Mo) alloys show an increased fracture toughness due to different toughening mechanisms. These mechanisms result from the fibrous or lamellar microstructure of the two constituting phases alpha-Cr(Mo) and beta-NiAl. However, the fracture toughness of the individual phases and the evolution from early crack growth to the toughening mechanisms have not yet been systematically studied. Herein, bending tests on focused ion beam (FIB)-notched microcantilever beams are used to characterize the small-scale fracture properties. The micromechanical investigations reveal that the fracture toughness of the alpha-Cr(Mo) phase (7.5-9.1 MPam) is much higher than the fracture toughness of beta-NiAl (2.2-2.9 MPam). Larger cantilevers in the crack arresting orientation show an enhanced fracture toughness with up to 14.4 MPam, which is still lower than the one of macroscopic experiments. This is attributed to the small interaction volume of the crack, which hinders the full exploitation of potential extrinsic toughening mechanisms.
Lamellar eutectic NiAl-Cr(Mo) alloys show an increased fracture toughness due to different toughening mechanisms. These mechanisms result from the fibrous or lamellar microstructure of the two constituting phases alpha-Cr(Mo) and beta-NiAl. However, the fracture toughness of the individual phases and the evolution from early crack growth to the toughening mechanisms have not yet been systematically studied. Herein, bending tests on focused ion beam (FIB)-notched microcantilever beams are used to characterize the small-scale fracture properties. The micromechanical investigations reveal that the fracture toughness of the alpha-Cr(Mo) phase (7.5-9.1 MPam) is much higher than the fracture toughness of beta-NiAl (2.2-2.9 MPam). Larger cantilevers in the crack arresting orientation show an enhanced fracture toughness with up to 14.4 MPam, which is still lower than the one of macroscopic experiments. This is attributed to the small interaction volume of the crack, which hinders the full exploitation of potential extrinsic toughening mechanisms.
Keywords
eutectic alloys, focused ion beam, fractures, intermetallic, micromechanics
