Twenty years of fun with resonant ultrasound

Resonant ultrasound (RUS) is an elegant method for determining the elastic and anelastic properties of materials. The development of computational methods, robust computer codes, and sensitive instrumentation by a few key players has resulted in a simple, yet powerful, tool. The speaker was introduced to RUS 20 years ago. During the past two decades he, along with numerous students and in collaboration with many colleagues, has used this technique to study various problems: phase transitions, texture in alloys, and the elastic and anelastic properties of several materials—hydrogen absorbing compounds and alloys, nanocrystalline materials, and quasicrystalline materials—over an extended temperature range. All of these problems would have been difficult, if not impossible, to address with conventional ultrasonic methods. A few examples—phase transitions and internal friction due to hydrogen hopping, in particular—will be used to illustrate the power of RUS.