| Continuous hot torsion tests of 10vol%SiC_P/Al-14Fe composites were performed in the range of 350∼530℃ and 1.15×10^(-3)∼1.15×10^(-1)/sec. Flow curves of the hot torsion tests were analysed with respect to the characteristics of work hardening rate θ, dynamic recrystallization (DRX) and constitutive equation. The critical strain (ε_c) for DRX initiation was determined from changes in slope of the strain hardening rate -effective stress (θ-σ) curves, and it was decreased with increasing temperature and strain rate. Although the SiC particles helped the initiation of DRX, they also retarded dynamic recrystallization progress. Relationship between critical strain and peak strain (ε_P) was found to be ε_c ＝ 0.51 ε_P. The stress dependence on the strain rate (ε˙) and temperature (T) could be described by hyperbolic sine relationship, ε˙=2.21×[sinh(1.92×10^(-2)·σ)]^(4.7)exp(-193.5 kJ/RT). The microstructural development during hot deformation were interpreted by dynamically recrystallized structures which were composed of equiaxed grains, subgrains and dislocation tangles. |
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