A Calibration Method of Micropillar Compression Testing for Taper and Eccentricity Induced Errors

Errors induced by pillar taper and eccentric load in micropillar compression experiments have seldom been investigated, although they significantly affect the measurement accuracy, especially in the testing of specimens in a micrometer and nanometer size. A novel calibration method related to stress–strain responses in micropillar compression testing was proposed in this study to eliminate this kind of errors. Axial load and eccentric load were applied to high-entropy alloy (HEA) pillars with taper angles of 1°, 2°, and 3°, respectively, and the measured stress–strain curves were corrected by the proposed calibration method. The results revealed that the difference of the corrected curves with different tapers or eccentricities was smaller than the measured curves. The errors induced by the taper and eccentric load increased with the taper angle and eccentricity. In addition, the difference between measured and corrected flow stresses increased with the taper angle, which was essentially consistent with the results from the calibration method.