Materials characterization at high temperatures using laser ultrasound

By short laser pulses (pulse duration: 1-100 ns and pulse energy: 1-500 mJ, typically) ultrasonic signals are generated in a contact free way and detected by an optical interferometer. From the signals obtained by the way the ultrasonic P- and S-velocities are deduced for calculation of the elastic constants. 600 In addition the reverberation field generated by scattering and multiple sidewall and backwall reflection is observed in order to determine the ultrasonic absorption (e.g. the dissipative part of the ultrasonic attenuaion). With this new technique, material characterization is possible up to very high temperatures. Ultrasonic absorption data and elastic constants in aluminum, SiC ceramic, and white cast iron are presented as a function of temperature up to 1400 K.