Bauschinger effect in α-γ dual phase alloys studied by in situ neutron diffraction

Abstract

In situ neutron diffraction experiments during tension-compression deformation were performed on five Fe-Cr-Ni alloys with the volume fraction of ferrite (α) ranging from 0.0 to 100%. Tensile deformation was applied in a step by step manner up to a strain of 1.3-2.0 % followed by compressive deformation, and neutron diffraction spectra were recorded during temporary stops of a deformation machine with fixed crosshead. (1 1 1) reflection of austenite and (1 1 0) of ferrite, respectively, were measured simultaneously by using a position sensitive detector. Elastic lattice strains in both constituent phases were evaluated from measured diffraction spectra as a function of external load. Based on these experimental results, heterogeneous deformation behavior in the α-γ dual phase alloys is discussed considering the Bauschinger effect. It is concluded that large compressive residual lattice strains detected in the γ phase after tensile pre-straining, causes the large Bauschinger effect in α-γ dual phase alloys.