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The high temperature deformation behavior of Al 6061 composites reinforced with SiC and Al2O3 particles has been studied in the temperature range of 300–550°C and the strain rate range of 0.1–3.0/sec by hot torsion test. The deformation efficiency η, given by (2 m/ m + 1), where m is the strain rate sensitivity, is calculated as a function of temperature and strain rate to obtain iso-efficiency contour map. The composite reinforced with SiC particle exhibited a domain of dynamic recrystallization (DRX) with a peak efficiency of ∼40% at the temperature range of 450–500°C and strain rate range of 0.2–0.5/sec. On the other hand, the composite reinforced with Al2O3 particle showed the DRX domain at the temperature range of 450–480°C and strain rate range of 0.1–0.2/sec. The characteristics of these domain have been investigated with the help of microstructural observation and hot ductility measurements. [ABSTRACT FROM AUTHOR]

Hot torsion test has been carried out for Al 2024 composite reinforced with 8 μm SiCp (15 vol.%) to suggest optimum hot working condition for dynamic recrystallization (DRX) at the temperature range of 320 to 520 °C and strain rate range of 0.1 to 3.0/sec. Flow curve and deformed microstructure have been analyzed to identify the hot restoration mechanism of DRX. Processing map showing the variation of the deformation efficiency expressed by [2 m/( m + 1)], where m is the strain rate sensitivity, with temperature and strain rate has been described for the composite. The characteristics of domain of DRX and peak efficiency of the composite have been analyzed by observing deformed microstructure. The composite showed 40–50% efficiency at the DRX domain (370–460 °C, 0.1–0.5/sec). Also, the variation of deformation efficiency with Zener-Hollomon parameter ( Z = έ exp( Q/ RT)) were discussed to find out optimum hot working condition for DRX of the composite. It is found that the optimum temperature and strain rate condition for DRX of the composite is 430–450 °C and 0.5/sec. [ABSTRACT FROM AUTHOR]