In-situ neutron diffraction study on a dislocation density in a correlation with strain hardening in Al–Mg alloys

It is well known that variations of alloy and microstructural parameters i.e., alloy composition and grain size are favorable ways to improve the mechanical properties in non-heat-treatable aluminum alloys including Al–Mg alloys. It leads to a change in stress-strain curve behaviors. The flow stress is mainly correlated with dislocation interactions. In this study, in-situ neutron diffraction experiment was conducted to study evolution of dislocation density and characteristics during tensile deformation of Al–Mg. The dislocation density and related characteristic i.e., dislocation rearrangement were quantitatively analyzed by using neutron diffraction line profile analysis with using Convolution Multiple Whole Profile (CMWP) method. Variations of solute (Mg) contents and grain sizes in Al–Mg were investigated in a correlation with the dislocation densities and dislocation interactions. The higher Mg content and smaller grain size resulted to higher dislocation density and, consequently, higher flow stress and strain hardening rate.