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G. Requena, E. Marks, E. Boller:
"Evolution of the Connectivity of the Phases in a Short Fibre reinforced Al-piston Alloy during Creep";
Talk: ESRF Users' Meeting, Grenoble - Frankreich (invited); 02-05-2008 - 02-07-2008.

The evolution of the microstructure during creep of an AlSi12CuMgNi alloy with 15 vol% of Al2O3 short fibres was investigated by means of synchrotron microtomography. The results reveal a change of the morphology of the hybrid reinforcement composed by the eutectic-Si, the short fibres and the intermetallic particles. This change takes place due to the diffusion induced coarsening of Si and a coarsening of the intermetallic particles. The interconnectivity of the hybrid reinforcement increases during long-term creep exposure reaching a degree of almost full interconnectivity after 6400 h of creep. The analysis of creep damage during secondary creep stage shows an increase of void volume fraction by a factor 2, while the number of voids per volume remains practically constant (void sizes larger than 8 voxels were analysed). An analysis of the voids´ location indicates that pores generated during processing of the composite grow, but no new pores are produced during the primary and secondary creep stages.