Elastic Moduli and Internal Friction of Low Carbon and Stainless Steels as a Function of Temperature.

Elastic (Young, shear and bulk moduli, Poisson's ratio and Lamé parameter), longitudinal and transverse internal friction values for low carbon steel and stainless steel were simultaneously measured over a temperature range 300-1500 K, by an ultrasonic pulse sing-around method. These elastic moduli decrease and Poisson's ratio increases with increasing temperature, suggesting activation of shear mode in a high temperature region. Longitudinal and transverse internal frictions are sensitive to recrystalization, and to α(ferritic)/γ(austenitic) phase transition and solution of precipitated carbide phases into the austenitic matrix, respectively. A relaxation peak with an apparent activation energy of 0.97 eV was observed at around 610 K for the carbon steel.