Anisotropic deformation of ZrB2 ceramic grains during in-situ micropillar compression up to 500°C

Conference Dates

October 1-6, 2017


Deformation behaviour of ZrB2 micropillars was investigated under ex-situ and in-situ micro compressions at room and elevated temperatures up to 500°C. Pillars were fabricated by focused ion beam (FIB) in large grains nearly basal and prismatic orientations which were selected by means of electron backscatter diffraction (EBSD). Micro-compressions were carried out by both ex-situ and in-situ nanoindenter machines equipped with flat punch diamond tips. In the latter case, the deformation process was simultaneously captured by a scanning electron microscope (SEM). At room temperature, ex-situ measurements revealed considerable anisotropy showing ~80% higher yield () and rupture () stress values for the basal oriented pillars (, ) compared to the prismatic pillars (, ). Careful analysis of the compressed pillars revealed the activation of the type slip system in prismatic orientation both in the form of single- and multiple-slip which has not been reported so far in the relevant literature. In-situ micro-compressions at elevated temperatures revealed that the rupture stress of basal pillars was comparable with that was measured at room temperature showing their catastrophic collapse with the presence of slight crystal plasticity (Fig.1). In case of prismatic oriented pillars, the scenario of slip activation controlled plastic deformation was acquired showing an increase deformation without failure with increasing temperature (Fig.1). Additionally, the yield and rupture stress values were significantly reduced down to at 500°C. These findings suggest that the slip activation in ZrB2 ceramic grains strongly depends on the temperature.

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