An analysis of the microstructure and reinforcement distribution of an extruded particle-reinforced Al 6061-10 volume percent A1O3 metal matrix composite

• Main Author: Longenecker, Fredric W.
• Other Authors: McNelley, Terry R.
• Language: en_US
• Published: Monterey, California. Naval Postgraduate School 2014
• Online Access: http://hdl.handle.net/10945/39970

Approved for public release; distribution is unlimited. === This research was performed in conjunction with funding by DURALCAN- USA through a Cooperative Research and Development Agreement (CRDA). The program seeks to improve the ductility of cast and extruded Al 6061-Al203 metal matrix composite (MMC) materials. Annealing stages were designed to be introduced into combined extrusion and drawing operations during the processing of the MMCs. This work has included a comprehensive analysis of a composite's microstructure as related to processing strains ranging from zero to 5.32 during extrusion/ drawing operations. As the strains were increased, particle clusters present in the as-cast material were dispersed and the particle distribution became more uniform. Strains of greater than 4.0 were required in order to disperse the clusters and substantially eliminate banding of the particle distribution. The recrystallized grain size in the Al matrix decreased as increased processing strain was applied to the material. The grain size appeared to be stable and resistant to coarsening during subsequent solution heat treatment. Quantitative image analysis revealed no change in apparent particle size or aspect ratio indicating no fracturing of the particles during processing. The image analysis revealed no readily measurable feature to be used to assess uniformity of the particle distribution.