A study of materials at high temperature using miniaturized resonant tuning forks

Miniaturized tuning forks, whose resonant frequencies are temperature dependent, have been manufactured from various materials using a precision milling machine under computer control. Two noncontact measurement systems that rely upon capacitive transducers as well as a pulsed ruby laser have allowed the generation and detection of fork vibrations at temperatures up to 900 °C. The usefulness of such a system for materials characterization will be demonstrated through the successful detection of the precipitation and dissociation of hydride platelets in a fork consisting of a Zr–Nb alloy. Also to be discussed are studies of single‐crystal silicon tuning forks and the resultant program currently underway for the development of micromachined thermometers for corrosive and high‐temperature environments.