The effect of H2SO4 on the stress exponent in ice single crystals

Abstract

AbstractSulphuric acid is a naturally occurring contaminant in ice. Recently, it was demonstrated that, during compression tests at −20°C and a strain rate of 1 × 10−5 s−1, as little as 0.1 ppm H2SO4 reduced both the peak strength and the subsequent flow stress of ice single crystals that deform primarily by basal slip. In the present work, compression tests were performed at −20°C at a variety of strain rates on both undoped ice single crystals and ice single-crystals containing 6.8 ppm sulphuric acid of various orientations again deforming primarily by basal slip. The results show that sulphuric acid dramatically decreases both the peak stress and the subsequent flow stress of ice single crystals at all strain rates. In contrast, the stress exponent was determined to be 1.89–1.97 and was unaffected by the dopant. This value is similar to values found by previous workers for undoped ice crystals.