Figure 5: Uniaxial micro-compression testing of n-B4C micropillars.
From: Enhanced mechanical properties of nanocrystalline boron carbide by nanoporosity and interface phases
(a) Representative engineering stress-strain curves of n-B4C pillars subjected to uniaxial micro-compression at a constant loading rate of 0.33 mN s−1. Typical stress-strain shown for the micropillar diameter of 1.6 μm (black curve), 2 μm (red curve) and 7 μm (dark cyan curve). The inserts show the detectable plastic yielding (~0.08–0.05%) of the pillars with different sizes. Scale bar of strain, 3%. (b) SEM micrograph of a representative n-B4C pillar fabricated by FIB milling, Scale bar, 1 μm. (c) The plot of measured strength values versus the diameter of n-B4C micropillars. All the n-B4C pillars show the failure strength above 4.5 GPa, much higher than that of dense microcrystalline B4C in the strength range marked by the red dotted lines (refs 5,29,30). (d) SEM micrograph of a compressed pillar, showing fragmentation via intergranular fracture. Scale bar, 1 μm.
