We describe a high-temperature, uniaxial creep apparatus designed to investigate nonlinear attenuation of materials over a wide range of temperatures (25-1300 °C) using forced oscillations combined with a bias stress. This apparatus is primarily designed for investigation of minerals and rocks with high melting temperatures. An oscillatory compressional stress is used to determine attenuation and Young’s modulus at frequencies of 10−1-102 Hz and high stress amplitudes (>0.1 MPa). Large bias stresses are applied in addition to the oscillatory stresses such that attenuation tests are conducted simultaneously with the ongoing creep. The complex compliance of the apparatus was characterized by conducting calibration tests on orientated crystals of sapphire. The real part of the apparatus compliance exhibits a dependence on sample length and frequency, whereas the imaginary part is only dependent on frequency. The complex compliance is not dependent on the oscillation amplitude or the bias stress. We assess the accuracy and precision of this calibration by comparing measurements of the attenuation and Young’s modulus of aluminum and acrylic to previously published values. We outline a set of criteria defining the conditions over which this apparatus can precisely determine the attenuation and Young’s modulus of a sample based on the sample length and expected values of attenuation and Young’s modulus.
Bibliographical noteFunding Information:
The authors wish to acknowledge the considerable effort from Physik Instrumente in the design and construction of this apparatus, including Geraint Green, John Hopkins, and Huw Prosser. Invaluable design and construction input was also provided by Jamie Long and James King in the Earth Sciences Workshop at the University of Oxford. This manuscript was improved by the insightful and constructive comments of two anonymous reviewers. R.C. acknowledges support from the Great Britain-China Educational Trust, Mineralogical Society of Great Britain & Ireland, and the Linacre Travel Fund. L.H. and C.T. acknowledge support from the Natural Environment Research Council (Grant No. 1710DG008/JC4). L.H. and D.W. acknowledge support from the Natural Environment Research Council (Grant No. NE/M000966/1). D.W. acknowledges support from the Netherlands Organisation for Scientific Research, User Support Programme Space Research (Grant No. ALWGO.2018.038). L.H. recognizes funds used to develop the apparatus from the John Fell Fund at the University of Oxford.
© 2021 Author(s).
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