The effect of shock-wave loading on transformation temperatures, elastic and anelastic properties of β1 Cu-Al-Ni martensitic single crystals

Abstract The effect of high-velocity impact loading on the structure, transformation temperatures, elastic and anelastic properties has been studied for a Cu-Al-Ni shape memory alloy in the β′1 martensitic phase. The impact loading of crystals has been performed by means of a light gas gun, producing compressive plane-strain wave pulses with a duration of about 2 × 10−6 s. The normal component of stress in the direction of the strain wave propagation ranged from 0.5 to 5 GPa and was used as a characteristic of the impact magnitude. The influence of the impact loading on the transformation temperatures and the structure of martenistic variants cannot be discerned in the present experimental results. In contrast with the macroscopic properties of crystals, the elastic and anelastic properties, studied at a frequency of about 100 kHz, are found to be strongly influenced by the impact loading. The difference between the effects of the impact on elastic and anelastic properties and on the macroscopic performance of crystals is interpreted on the assumption that these properties are related to different structural entities. Changes in the system of partial dislocations in the faulted martensite and variations in internal stresses are considered as basic contributors to the observed elastic and anelastic effects. The stability of the temperature range and hysteresis of the martensitic transformation are ascribed to the rather stable (under the present impact conditions) martensitic variant structure.