Abstract
Conventional high temperature creep rupture tests on a commercially produced metal matrix composite and a wrought unreinforced equivalent alloy indicate significant differences in behaviour. At typical creep service loads the performance of the reinforced alloy is superior. This performance is associated with a decrease in the ductility to failure and a very high power law exponent. At high stresses the creep performance breaks down, and higher creep rates than those in the comparable matrix alloy, and hence lower creep lifetimes, are shown. It is proposed that this behaviour may be associated with reduced interparticle plasticity due to the reiriforcement phase, up to a critical applied stress beyond which creep plasticity is enhanced. In this regime, the added reinforcing particles distribute plastic strain throughout the material, and postpone localised plastic instability until higher total strain values. This results in higher creep rates and higher strains to rupture.
MST/3191
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