On the importance of sample compliance in uniaxial microtesting

Recent investigations have reported significantly higher flow stresses for microcompression compared to microtensile testing. To clarify this point a load reversal test was performed on a microtensile specimen and equal flow stresses in tension and compression were observed. In contrast, if the lateral sample compliance constrains the deformation, microcompression testing overestimates the flow stresses. Additional contributions to the measured flow stresses stem from the aspect ratio of the sample and dislocation pile-ups.