Measurement and prediction of residual stresses in a titanium metal matrix composite ring

Residual strain measurements have been carried out on a fibre reinforced Ti-6Al-4V (Ti-6-4) ring upon fabrication and after machining. As the composite is embedded in Ti-6-4 cladding, neutron diffraction is the only non-destructive technique able to measure residual strains within the composite region. Experimental results indicate that measurements can be made as far as 10 mm below the surface using a large gauge volume and long count times. An axisymmetric finite element model has been constructed, to predict the residual stress state on cooling from consolidation phase and after machining, which incorporates thermal, elastic and creep properties of the constituent materials. Model predictions are in good agreement with experiments.