ACOUSTIC EMISSION DURING DEFORMATION AND FRACTURE OF THREE NAVAL ALLOY STEELS.
The acoustic emission (AE) behavior of three naval alloy steels (HY 80, HY 100, and HY 130) was characterized during tensile elongation and bend-type loading. The detection of emissions was accomplished using a very new, state-of-the-art interferometer supplied by the Johns Hopkins Applied Physics Laboratory as well as by using a unique piezoelectric transducer. All three steels investigated were found to exhibit very similar deformation and fracture modes despite a slight difference in microstructures. They also exhibited identical AE behavior within statistical variances. Their fracture consisted of a very ductile mode involving void coalescence and growth with final failure occurring by knife-edge rupture of numerous microligaments between voids. Two major types of AE were detected. All three steels also exhibited an appreciable Kaiser effect on reloading.