SCIENCE AND ENGINEERING OF COMPOSITE MATERIALS, cilt.10, sa.4, ss.279-286, 2002 (SCI-Expanded)
The material tested in this work is AA 6063 alloy reinforced with particulate silicon carbide (SiC). The material was produced by a stirring casting technique, which gives rise to composites with a uniform distribution of SiC throughout the matrix. The hot workability of AA 6063 composites reinforced with different volume fractions ( 5, 10,and 15 %) of SiC was investigated by torsion tests in 230-480 degreesC under strain rates 0,2-5 s(-1). The microstructure before and after the deformation was investigated using optical microscope and scanning electron microscope (SEM). The equivalent stress decreases uniformly with increasing deformation temperature for AA 6063 alloy and all composites. The addition of the SiC to an AA 6063 matrix alloy increased the dislocation density, resulting in a high equivalent stress and a low equivalent strain for the dynamic recovery (DRV) and local dynamic recrystallisation (DRX) of composites. From the flow curves and hot-deformed microstructures, it was found that DRV and DRX were responsible for the hot restoration of the composites.