Neutron diffraction measurements of time-dependent residual stresses generated by severe thermomechanical deformation

Residual stresses were generated by severe thermomechanical deformation in an aluminum alloy plate. The evolution of the residual stresses during natural aging was investigated by neutron diffraction up to 10,000 h. A data reduction method was developed to eliminate microstructure influences (solute variations) on the lattice spacing changes, thereby allowing the determination of the long-range macroscopic residual stresses. The residual stress decreased (∼25 MPa) with time due to the microstructural modification within the deformed region during natural aging.