Influence of high-energy impact actions on the elastic and anelastic properties of martensitic Cu-Al-Ni crystals

The influence of high-energy impact shock-wave loading on the microplastici ty and macroscopic performance of the Cu-AI-Ni crystals in the beta(1)' mar tensitic phase has been studied. Elastic and anelastic properties of quench ed and aged polyvariant single crystals before and after impact shock-wave loading were measured in the temperature range 80-300 K, at a frequency of about 100 kHz in the strain amplitude-independent and amplitude-dependent r anges by means of the composite oscillator technique, and in the MHz freque ncy range using the pulse-echo technique. High-velocity impact loading of t he specimens was realised by plane shock-waves with stress pulses with a du ration of similar to 2 . 10(-6) s and stress amplitudes up to 5 GPa. A pron ounced influence of impact shock-wave loading on the elastic and anelastic properties of the beta(1)' martensite has been observed. A strongly marked softening of the material and an enhancement of damping properties are reve aled up to the highest stress pulse amplitudes. This behaviour differs fund amentally from the one observed in 'ordinary' fcc metals. Changes of the de fect structure induced by shock-wave loading, which may be responsible for the observed phenomena, have been discussed. (C) 2000 Published by Elsevier Science S.A.