Prismatic, basal, and slip strengths of commercially pure Zr by micro-cantilever tests

By J. Gong, T. Benjamin Britton, M. Cuddihy, Fionn P.E. Dunne, A. Wilkinson. 2015

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Abstract Slip strengths of 〈a〉 basal, 〈a〉 prism, and 〈c+a〉 pyramidal systems in commercially pure zirconium have been determined using micro-cantilever testing. A range of single crystal cantilevers 0.5 μm to 10 μm wide, oriented for single slip were prepared using focused ion beam (FIB) machining and subsequently deflected using a nanoindenter. The critical resolved shear stress ( τ crss ) was found by fitting a crystal plasticity finite element model to the experimental load–displacement data for these micro-bending tests. All the three slip systems in α-Zr show a marked size effect in bending described well by τ CRSS ( W ) =  τ 0  +  AW n , where W is the cantilever width, τ 0 is the CRSS at the macro scale and n  = ∼−1. The exponent, n , of near −1 is in good accord with hardening caused by the back stress generated by dislocations piling up at a diffuse barrier caused by the reduction of stress near the neutral axis. The macro scale CRSS values were used to successfully simulate deformation of a conventional macroscopic compression test.

Subfields: Ceramics and Composites, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/f98361747e7439b9a62a41efc727c2b45ccb21d7