Internal friction in Cu-Al-Ni crystals in martensitic phase and during temperature-induced martensitic transformation

Temperature and oscillatory strain amplitude dependences of the ultrasonic amplitude-dependent internal fiction and oscillatory anelastic strain at temperatures 6.5-300K have been studied in Cu-Al-Ni single crystals in martensitic phase. An anomalous behaviour of the amplitude dependent internal friction and effective Young modulus was revealed in quenched crystals: the amplitude dependent internal friction decreases with temperature increase at all temperatures and strain amplitudes investigated, and the Young modulus increases notably with temperature from 70 to 200K. The anomalies in the ADIF and effective Young modulus behaviour are attributed to peculiarities of dislocation dynamics.