Micropillar compression of Ti(C,N)-FeNi cermets: Microstructural, processing, and scale effects

Besharatloo, H.; de Nicolás-Morillas, M.; Chen, M.; Mateo, A.; Ferrari, B.; Gordo, E.; Jiménez-Piqué, E.; Wheeler, J. M.; Llanes, L.

Journal of the European Ceramic Society (2022)

The influence of microstructure and processing route on the small-scale mechanical response as well as on the deformation and failure mechanisms of Ti(C,N)-FeNi cermets were investigated by uniaxial compression of micropillars milled by focused ion beam with different sizes. Stress-strain curves were determined and associated deformation mechanisms were observed in-situ using scanning electron microscopy. The appropriate micropillars dimension was assessed, based on the microstructural characteristics of studied cermets, to overcome scale effect issues. A direct relationship was observed between yield strength and ceramic/metal ratio for colloidal samples. Meanwhile, deformation of metallic binder and glide between Ti(C,N)/Ti(C,N) particles were evidenced as dominant mechanisms during the compression for colloidal cermets with 70 and 80 vol% of ceramic phase, respectively. The obtained results illustrate that samples processed from powder attained by colloidal route provide superior mechanical behavior, as compared to that exhibited by specimens shaped following a conventional powder metallurgy one (wet ball-milling/drying).