Local Deformation Energy and Void Formation Behavior in 16%Cr Ferritic Steel

Abstract

Tensile tests of 16mass%Cr bearing ferritic steels were performed in order to investigate the effect of the mean interparticle spacing (λ) on the local deformation energy. λ of Cr precipitates was changed from 3.3 to 5.1 μm. The amounts of Cr precipitates in the specimens tested were controlled to be the same level.
The local deformation energy was increased with increasing λ in the specimens without a notch, while the local deformation energy does not depend on λ for the notched specimens.
AsB (Angle selective Backscattered Electron Detector) images of voids beneath the fracture surface showed that the difference of the local deformation energy dependence on λ between notchless and notched specimens was due to the void coalescence processes. This finding reveals that the local deformation energy is influenced by the stress triaxiality through the void coalescence behavior.