Shock-wave compression of x-cut quartz as determined by electrical response measurements

Abstract

The mechanical response of x-cut quartz in the vicinity of the Hugoniot elastic limit is determined from measurements of the piezoelectric current from samples impact loaded from 26 to 130 kbar. The Hugoniot elastic limit is determined to be 60 −1·5 +3 kbar at a compression of 0·066 −0·002 +0·004 This Hugoniot elastic limit corresponds to a shear strength of 5·5 per cent of the C 44 shear modulus. For stresses well above the Hugoniot elastic limit the electrical current measurements show that the material exhibits a substantial reduction of shear strength. The pressure derivative of the bulk modulus is determined to be 4·5, substantially less than the ultrasonic value. The experimental records show evidence for a time delay for reduction of shear strength which varies from about 10 −7 sec immediately above the 60 kbar Hugoniot elastic limit to about 10 −8 sec for stresses well above the Hugoniot elastic limit. The measurements also show stress relaxation below the Hugoniot elastic limit between 40 and 60 kbar.