An analytic description of the creep deformation of metals in the ultrasonic field

The effect of superimposed ultrasonic vibration on the primary creep of metals is modeled in terms of the synthetic theory of irrecoverable deformation. We consider two sonication modes: (i) the ultrasound acts continuously during the deformation, and (ii) the ultrasound is periodically on and off. Whereas both cases show a significant increase in primary creep, the periodical sonication leads to higher deformation values. To catch the phenomenon of ultrasound-assisted creep, we extend the flow rule equation by a term that accounts for the process occurring on the microlevel of material induced by ultrasound.