Temperature dependence of internal damping of austenitic steel in different states

Abstract This study investigates the internal damping behavior of three austenitic stainless steels: AISI 304, AISI 316L, and AISI 316Ti. Temperature-dependent internal damping was measured in the range of 25–400 °C using hourglass-shaped specimens, in the initial state, after heat treatment and after plastic deformation. The measurements were carried out with an ultrasonic resonance apparatus operating at a frequency of approximately 20,450 Hz. The results demonstrate that internal damping provides valuable information about microstructural changes occurring in austenitic steels. Temperature variations enable the study of processes such as precipitation, recrystallization, dissolution of structural components, as well as transformation of deformation-induced martensite. Internal damping is closely related to microplasticity and energy dissipation within the material, allowing evaluation of elastic properties, stress relaxation, and the kinetics of fatigue damage accumulation under long-term loading. The findings highlight the relevance of internal damping analysis for understanding structural stability and mechanical behavior of commercially available stainless steels, which are widely used not only in automotive engineering but also as biomaterials in medical applications.