Towards understanding anelasticity of the beta(1)' martensitic phase of Cu-Al-Ni

The present work continues the series of experimental investigations undert aken in order to elucidate the mechanisms controlling elastic and anelastic properties of the beta(1)' martensitic phase of Cu-based shape memory allo ys. The paper reports an attempt to distinguish between 'dislocation' and ' interface' mechanisms of the internal friction in the beta(1)' martensitic phase of Cu-Al-Ni single crystals. Two types of experiments have been perfo rmed. First, the ultrasonic strain amplitude-independent and amplitude-depe ndent internal friction (ADIF) of a monovariant specimen for temperatures 9 0-300 K is carefully re-examined. Second, in situ measurements of the ADIF and of the influence of ultrasonic oscillations on the plastic deformation (acoustoplastic effect) were carried out during quasistatic deformation of a quenched polyvariant specimen. Experimental results support a dislocation rather than an interface mechanism of anelasticity, at least at ultrasonic frequencies and moderate strain amplitudes. (C) 2000 Elsevier Science S.A. All rights reserved.