Mechanical behavior during aging of plastically deformed AA6061-SiCp composite in different temperatures

Abstract

In this study, the kinetics of aging in AA6061 and AA6061 with 5% volume fraction SiCp were studied and compared. The composite was first produced and homogenized using stir casting technique followed by hot extrusion with the ratio of 18:1. Then, both AA6061 and the composite were aged at three different temperatures including room temperature, 170 °C and 240 °C, while mechanical properties during aging were evaluated employing hardness measurements and tensile testing. Moreover, in order to assess the effect of plastic deformation on the kinetics of aging, a series of samples were first deformed by equal-channel angular pressing immediately after solution treatment and then aged in the above-mentioned temperatures. The results indicate that the aging activation energy of the composite is reduced from 108.7 to 80.5 kJ/mole when the composite is subjected to cold deformation prior to aging. Furthermore, a combination of equal-channel angular pressing and subsequent aging at 170 °C gives the highest strength with the moderate ductility compared to the undeformed composite and the original AA6061.