Processing and microstructure of metal matrix composites prepared by pressureless Ti-activated infiltration using Fe-base and Ni-base alloys

Metal matrix composites (MMC) were produced by activated pressureless melt infiltration. Ti-activated pressed Al2O3 powder compacts were infiltrated with several Fe-base or Ni-base alloys to investigate the influence of single alloying elements on the infiltration process and the resulting MMC structure. While it was found that there are minor differences in the infiltration behaviour of the single alloys, infiltration quality and the obtained MMC microstructures were more strongly influenced by the initial activator amount and the dwell time of the process than by the infiltrate itself. Fe-base alloys as well as Ni-base alloys were found suitable for Ti-activated melt infiltration using Al2O3 ceramic.