Fracture toughness evaluation of NiAl single crystals by microcantilevers-a new continuous J-integral method

Ast J, Merle B, Durst K, Göken M (2016)

Publication Status: Published

Publication Type: Journal article

Publication year: 2016

Journal

Journal of Materials Research Cambridge University Press (CUP) / Materials Research Society

Publisher: CAMBRIDGE UNIV PRESS

Book Volume: 31

Pages Range: 3786-3794

Journal Issue: 23

URI: https://opus4.kobv.de/opus4-fau/files/8989/Ast_fracture_toughness.pdf

DOI: 10.1557/jmr.2016.393

Abstract

The fracture toughness of NiAl single crystals is evaluated with a new method based on the J-integral concept. The new technique allows the measurement of continuous crack resistance curves at the microscale by continuously recording the stiffness of the microcantilevers with a nanoindenter. The experimental procedure allows the determination of the fracture toughness directly at the onset of stable crack growth. Experiments were performed on notched microcantilevers which were prepared by focused ion beam milling from NiAl single crystals. Stoichiometric NiAl crystals and NiAl crystals containing 0.14 wt% Fe were investigated in the so-called "hard" orientation. The fracture toughness was evaluated to be 6.4 +/- 0.5 MPa m(1/2) for the stoichiometric sample and 7.1 +/- 0.5 MPa m(1/2) for the iron containing sample, indicating that the addition of iron enhances the ductility. This effect is intensified with ongoing crack propagation where the Fe-containing sample exhibits a stronger crack resistance behavior than the stoichiometric NiAl single crystal. These findings are in good agreement with macroscopic fracture toughness measurements, and validate the new micromechanical testing approach.

Authors with CRIS profile

Johannes Ast Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Benoit Merle Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Karsten Durst
Mathias Göken Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Additional Organisation(s)

Exzellenz-Cluster Engineering of Advanced Materials Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Related research project(s)

In-situ nanomechanics and FIB tomography of thin films (EXC315 EAM (A2-3)) Exzellenz-Cluster Engineering of Advanced Materials Nov. 1, 2012 - Oct. 31, 2017

Involved external institutions

Technische Universität Darmstadt DE Germany (DE)

How to cite

APA:

Ast, J., Merle, B., Durst, K., & Göken, M. (2016). Fracture toughness evaluation of NiAl single crystals by microcantilevers-a new continuous J-integral method. Journal of Materials Research, 31(23), 3786-3794. https://dx.doi.org/10.1557/jmr.2016.393

MLA:

Ast, Johannes, et al. "Fracture toughness evaluation of NiAl single crystals by microcantilevers-a new continuous J-integral method." Journal of Materials Research 31.23 (2016): 3786-3794.

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