Prediction of dynamic recrystallization condition by deformation efficiency for Al 2024 composite reinforced with SiC particle

Hot torsion test has been carried out for Al 2024 composite reinforced with 8 mu m SiCp (15 vol.%) to suggest optimum hot working condition for dynami c recrystallization (DRX) at the temperature range of 320 to 520 degrees C and strain rate range of 0.1 to 3.0/sec. Flow curve and deformed microstruc ture have been analyzed to identify the hot restoration mechanism of DRX. P rocessing map showing the variation of the deformation efficiency expressed by [2m/(m + 1)], where m is the strain rate sensitivity, with temperature and strain rate has been described for the composite. The characteristics o f domain of DRX and peak efficiency of the composite have been analyzed by observing deformed microstructure. The composite showed 40-50% efficiency a t the DRX domain (370-460 degrees C, 0.1-0.5/sec). Also, the variation of d eformation efficiency with Zener-Hollomon parameter (Z = (epsilon) over dot exp(Q/RT)) were discussed to find out optimum hot working condition for DR X of the composite. It is found that the optimum temperature and strain rat e condition for DRX of the composite is 430-450 degrees C and 0.5/sec. (C) 2000 Kluwer Academic Publishers.