Slip activation controlled nanohardness anisotropy of ZrB2 grains
September 17-20, 2017
The orientation dependence of hardness and modulus of ZrB2 grains were determined on a polycrystalline ZrB2 specimen with low porosity using Berkovich nanoindentation at room temperature. Additionally, Cube corner indentation was carried out on differently oriented grains to generate visible slip patterns which were used to analyse slip activations. To describe the orientation dependence of nanohardness, an analytical model is proposed based on the activation of multiple slip system families. Based on literature data and the present indentation results, only the , and type slip system families were considered in the model. Simulations showed that none of the three slip systems by itself could describe the orientation dependence of the hardness of ZrB2. Analysis of the model in combination with the results of Cube corner indentation revealed that the experimental results can be appropriately described by the simultaneous activation of the , slip systems. Further analysis of the model together with first principles calculations found in the literature, were used to derive the hierarchy of slip activations of ZrB2 at room temperature.
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Tamás Csanádi, Ján Dusza, William G. Fahrenholtz, and Gregory E. Hilmas, "Slip activation controlled nanohardness anisotropy of ZrB2 grains" in "Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV", Jon Binner, The University of Birmingham, Edgbaston, United Kingdom Bill Lee, Imperial College, London, United Kingdom Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/uhtc_iv/25