Cluster analysis of acoustic emissions measured during deformation of duplex stainless steels

Abstract

Aiming at better understanding of the deformation mechanisms involved into plastic deformation of duplex stainless steels, acoustic emission (AE measurements were performed during room temperature tensile deformation of model steels and alloys with different phase structure including single phase α Fe30Cr and γ SUS316L steels and duplex α-γ SUS329J4L, Fe 24Cr24Ni alloys. The real time AE investigations were complemented by microscopic investigations of deformed microstructures. The quantitative AE analysis revealed different AE patterns which were correlated with underlying deformation mechanisms and microstructural transformations. The cluster analysis of AE power spectral densities has been proven effective in revealing specific groups of signals (clusters which appear on different deformation stages in different steel variants, which can be correlated with involved source mechanisms of plastic deformation and microstructural processes including dislocation slip in either fcc or bcc lattice of α or γ phase, respectively, twinning in the SUS 316L steel and α-γ A martensitic transformation in the Fe24Cr24Ni model alloy. © 2013 The Japan Institute of Metals.