The Influence of Morphology and Volume Fraction of Martensite on AE Signals during Tensile Loading of Dual-Phase Steels

In this paper, the failure mechanisms of Ferrite- Martensite dual-phase steels composite microstructure with various morphologies (Fibrous or Equiaxed) and volume fractions of martensite second phase (VM) (between 11- 70%) are investigated. These failure mechanisms consist of Ferrite-Martensite interface debonding and/or Martensite phase fracture. In each sample with a different morphology and VM, the failure mechanism is unique. For better study of these failure mechanisms, Acoustic Emission (AE) monitoring is used during tensile testing of several dual- phase steels with Fibrous and Equiaxed morphologies (each morphology is set with four VM) and attempted to relate the AE signals to various failure mechanisms. From AE measurements and FFT analysis, the AE signals associated with various failure mechanisms are classified on the basis of peak frequency. This study shows a good relationship between the AE signals and mechanisms of failure in various dual-phase steels.