In situ neutron diffraction during tensile straining of fine grained ferrite - pearlite steel

Abstract

In situ neutron diffraction during tensile deformation was performed on a steel with ferrite grain size 3.6 μm, which was close to the achievable minimum size for a ferrite - pearlite structure. The lattice plane strain, microstrain related to dislocation density, and the size of coherently diffracting blocks related to dislocation cell size were determined from the profile analysis of (110) diffraction spectra, as a function of the applied stress. The change in lattice plane strain revealed that grain refining strongly influences ‘grain to grain yielding’ behaviour with respect to Luders deformation. The increase in dislocation density estimated in the uniformly extending regime was similar to that observed in another specimen with ferrite grain size 46.2 μm.