Use of Compression-Bending Fracture Geometry to Study the Effects of Stoichiometry on Fracture Toughness of β-NiAl

Abstract

Compression-bending fracture geometry is a stable fracture geometry, which can enable the study of crack propagation and associated processes, such as crack bridging and microstructural and compositional inhomogeneity induced variation of fracture toughness and R-curve behavior. It was observed that surface friction strongly influences the fracture behavior of this geometry. The existing equation of Mode I stress intensity factor, KI, has been found to be accurate for the case of very low platen-sample surface friction and a narrow range of crack length. The fracture toughness of bulk polycrystalline β-NiAl of two compositions was measured using this geometry. The measured values of fracture toughness of Ni-50Al and Ni-40Al are 1.7 ± 0.6 and 4.3 ± 1 MPa m0.5, respectively. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.