Residual stress analysis in aerospace MMC materials by neutron diffraction

We studied the effect of the forming process and thermal treatment on the residual stress state of an extruded metal matrix composite component for aerospace application made of AA2009+25% SiCp. We proceeded in two steps, first studying the material as received (cast billets), then studying components of ideal shape, both as extruded and after stress annealing. The micromechanical model developed in parallel can predict the stress and strain levels in the component. The experimental results obtained on the billet have been used as input for this model. The major output which it was aimed at is an optimized production process. Residual strain scanning and finite-element method simulations give essential information to this end. We observed that, after T4 thermal treatment, the macrostresses relax in the radial and hoop directions while remaining constant in the axial one. Nevertheless, both the tensile microstresses in the Al phase and the compressive microstresses in the SiC phase increase.