Low-stress Wave Speed Measurements

Measurements of wave speeds at low stresses are often overlooked due to the difficulty of data collection and analysis. For some materials a simple extrapolation of higher-stress data to low stress states is reasonable, but for others phase changes and other complex behaviors can make this approach difficult and inaccurate. We present here a discussion of a new technique to measure wave speeds at low stress in copper and steel. This technique allows low stress wave speeds to be determined with an uncertainty of better than 1%. We will present results from measurements using this technique. We will compare polycrystalline and single crystal (of various orientations) copper wave speeds at low stresses. We will also put forward results from measurements of polycrystalline steel alloys.