Fatigue crack growth of WC–Co cemented carbides: a comparative study using small indentation flaws and long through-thickness cracks

• Published in: International journal of fracture Vol. 246; no. 2-3; pp. 293 - 307
• Main Authors: Mahani, S. Fooladi, Liu, C., García-Marro, F., Lin, L. L., Cabezas, L., Wen, X., Mansilla, N., Llanes, L.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2024; Springer Nature B.V
• Subjects: Automotive Engineering; Cemented carbides; Characterization and Evaluation of Materials; Civil Engineering; Classical Mechanics; Comparative studies; Crack propagation; Cracks; Cyclic loads; Engineering; Fatigue cracks; Fatigue failure; Fatigue tests; Fracture mechanics; Fracture surfaces; Indentation; Investigations; Materials fatigue; Mechanical Engineering; Mechanics; Metal fatigue; Metal forming; Residual stress; Thickness; Tungsten carbide; WC–Co cemented carbides; Fatigue crack growth; Small indentation flaws; Long through-thickness cracks; Fatigue micromechanisms
• ISSN: 0376-9429; 1573-2673
• DOI: 10.1007/s10704-024-00777-4

The fatigue crack growth behavior of a submicron-grained WC–Co hardmetal is investigated by artificially introducing small flaws by means of sharp indentation. Similar fatigue testing is also conducted on notched specimens with long through-thickness cracks for comparison purposes. The use of controlled small indentations flaws is shown to be a valid and successful approach for studying and describing crack growth behavior under cyclic loading for the material under consideration. This statement is based on the similitude found in fatigue mechanics and mechanisms between both crack types. Regarding the former, accounting of the indentation-induced residual stresses is key to rationalize the experimental findings. Concerning the latter, inspection of crack-microstructure interaction as well as fracture surfaces permit to discern similar features and scenarios, at both meso- and micrometric length scales. Results from this research yield an immediate practical implication, as indentation techniques may then be proposed as an alternative testing route for investigating fatigue crack growth behavior of hardmetal grades where sharp indentation is capable to induce well-developed radial crack systems.