The effect of phase transformations induced by cyclic loading on the elastic properties and plastic hysteresis of austenitic stainless steel

- Strain-induced martensitic transformation actively affects the acoustic characteristics.
- The relation between stress cycle amplitude and the change in Poisson's ratio is approximated by a linear.
- We proposed to determine the fatigue life of the material by the acoustic method.

The effect of low-cycle fatigue on the elastic and acoustic characteristics of austenitic stainless steel AISI 321 is investigated. The relation between characteristics of the hysteresis loop and changes of the acoustic parameters is established. A change of the elastic characteristics of austenitic stainless steel associated primarily with martensitic transformations that affect cyclic hardening, the width of the hysteresis loop, energy loss in the cycle, and the accumulated energy density is found. The influence of the amplitude of strain cycle on development of the elastic anisotropy is analyzed. The relationship between changes of elastic characteristics and damage is suggested; it can be used for evaluation of fatigue life by the acoustic method.