Effect of Thermomechanical Processing on Mechanical Properties of a Cast 6061Aluminum Metal Matrix Composite

摘要

Thermomechanical processing was conducted on cast 6061 Al-A12O3 metal matrixcomposites (MMCs) containing either 10 or 20 volume percent of alumina (A1203) particles. These materials were provided by DURALCAN-USA, Inc., of San Diego, CA in conjunction with a Cooperative Research and Development Agreement (CRDA) program on ductility enhancement for these MMCS. Processing included isothermal forging and rolling of materials at 500 deg C, with interpass anneal (IPA) times of 5 or 30 minutes. Isothermal rolling was also accomplished on 1.0 inch thick 6061-T6 Al plate. Processed materials were solution heat treated at temperatures ranging from 480-560 deg C, and were then age hardened at 160 deg C. Tensile testing was conducted to evaluate strength and ductility. Homogeneity of the particle distribution was improved by processing for both composites and no microstructural damage was apparent. Lower solution heat treatment temperature provided significant ductility enhancement while the longer IPA time at 500 deg C had a minor beneficial effect. As the percentage of reinforcement increased, aging time to peak strength decreased; peak strength, and yield strength increased; and ductility decreased. As the solution heat treatment temperature was decreased ductility was enhanced at a cost of peak strength. 6061 Al-A1203