THE INFLUENCE OF THERMAL-MECHANICAL PROCESSING ON RESIDUAL-STRESSES IN TITANIUM MATRIX COMPOSITES

The effects of three distinct thermo-mechanical processes on the resid ual stress state in a uni-directionally reinforced SCS-6/Ti-6-2-4-2 [0 ](6) titanium-alloy matrix composite were predicted using a finite ele ment model. For comparison the residual stresses were measured using X -ray and neutron diffraction. Reductions in stress were predicted by t he models and both experimental techniques recorded a reduction compar ed to the as-fabricated material. While the numerically predicted tren ds qualitatively agreed with the neutron measurements quantitative agr eement was not achieved. In the longitudinal direction the neutron res ults showed closer agreement to the calculation whereas in the transve rse direction the X-ray results did. Nevertheless the changes did corr elate with improvement in fatigue lifetimes. (C) 1997 Elsevier Science S.A.