Indentation creep in a short fibre-reinforced metal matrix composite

Creep properties of an unreinforced M124 (AlSi12CuMgNi) base alloy and an Al203 (Saffil) fibre reinforced M124+s metal matrix composite (MMC) were investigated by indentation tests performed between 250 and 350°C. It has been found that the creep curve of the base alloy consists of two stages (transient and steady state), whereas the curve of the composite material contains a decelerating third stage as well. This creep behavior is correlated with the changes of the microstructure below the indenter during the deformation process. In the region of steady state creep the stress exponent and the activation energy was determined for both materials.