| The present study aims at investigating powder metallurgy (P/M) fabrication processes of high performance 2009 Al composites reinforced with SiC particulates. In particular, the effect of consolidation temperature during the composite processing on microstructure and mechanical properties has been focused on. Rapidly solidified 2009 Al powders produced by commercial atomization technique were mixed with SiC particulates using a fluidized zone mixer. Composite billets were consolidated using a vacuum hot press at the temperature range from 560℃ to 620℃ under the pressure of 50 MPa, and then extruded at 450℃. Using the hot pressing temperature of 560℃, good quality Al-SiCp composite billets having relatively homogeneous microstructure and sound Al/SiC interfacial bonding were obtained, while the composite billets consolidated at the higher temperatures contained SiC depleted regions because of the larger amount of liquid. These SiC depleted regions were not removed during the extrusion process, resulting in the unhomogeneous distribution of SiC particulates. The better mechanical properties of the extruded bars were achieved in the composites fabricated with the lower consolidation temperature since they had the uniform distribution of SiC reinforcements together with full densification. Microstructure and mechanical properties were compared with those of the composites processed by Advanced Composite Materials Corp. or the composites reinforced with SiC whiskers so as to obtain a proper perspective of the Al-SiC composites. |
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