Towards understanding anelasticity of the β 1′ martensitic phase of Cu–Al–Ni

Abstract

The present work continues the series of experimental investigations undertaken in order to elucidate the mechanisms controlling elastic and anelastic properties of the β 1′ martensitic phase of Cu-based shape memory alloys. The paper reports an attempt to distinguish between ‘dislocation’ and ‘interface’ mechanisms of the internal friction in the β 1′ martensitic phase of Cu–Al–Ni single crystals. Two types of experiments have been performed. First, the ultrasonic strain amplitude-independent and amplitude-dependent internal friction (ADIF) of a monovariant specimen for temperatures 90–300 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.