Mechanical and Piezoelectric Properties of Shock-Loaded X-Cut Quartz at 573°K

Abstract

The mechanical and piezoelectric properties of uniaxially strained X‐cut quartz were studied at 573°K over a stress range of 6 to 21 kilobars by monitoring the current output from a shock‐loaded quartz disk. In addition to providing fundamental knowledge of the behavior of quartz under these conditions, the results yield data necessary for the application of quartz as a submicrosecond stress gauge at this temperature. The elastic wave velocity was found to be 5.70 mm/μsec at 573°K, a 0.35% decrease from the room temperature value. The piezoelectric factor relating the piezoelectric charge to stress was determined as k = (1.895×10⁻⁸+1.470×10⁻¹⁰σ_x) C/(kilobar‐cm²). This value is based on room temperature values of the electrode area and the gauge thickness. In the zero stress limit, the piezoelectric factor determined by shock loading compares favorably with the e₁₁/c₁₁ piezoelectric coefficient of quartz. Above 14 kilobars, relaxation in the current output of the quartz was observed. Therefore, when using quartz as a gauge at 573°K at higher stresses, some caution must be exercised in interpreting the entire stress‐time history recorded. This relaxation in current does not affect the precision of the quartz gauge for the measurement of step‐input stresses. One experiment performed at 17 kilobars and 743°K indicates the usefulness of the quartz gauge at this temperature.