2. EXPERIMENTAL
2.1 High frequency elastic properties
The high elasticity/low hardness of PRR makes conventional static/low strain rate techniques for determination of elastic properties (e.g. tensile testing) problematic. Consequently, ultrasonic techniques have been applied here. Wave velocities were measured using a Panametrics 500PR pulse receiver together with appropriate 1 MHz Panametrics transducers, which along with measured densities allowed calculation of elastic properties [9]. Signal attenuation was overcome by using thin 3-6 mm thick targets and a transmit/receive transducer configuration. Accuracy was further increased by accounting for signal delay in the transmitter and receiver transducer wear plates (achieved by comparison of measured wave velocities of standards such as Cu to known literature values).