Kyu Hwan Oh

High temperature deformation behavior in a 2124Al15VOL%SiCw composite

One of the interesting properties of Al/SiC composites is a superplastic-like behavior or an extended ductility in a two-phase (solid + liquid) region. Mahoney and Ghosh reported that a 7475Al/SiC[sub p] (subscript p represent particulate) could be superplastically deformed up to 450% at 500[degree]C. The matrix itself was a superplastic material, which made it possible for the composite to be superplastically deformed. Wu and Sherby reported a superplasticity in 2024Al/SiC[sub w](subscript w represents whisker) under a thermal cycling condition, which was attributed to internal stresses. The above superplastic behaviors were obtained at very slow strain rates. On the other hand, Chokshi et al. reported that elongation of a 2124Al/SiC[sub w] increased with increasing strain rate up to 10[sup [minus]1]sec[sup [minus]1] at 475[degree]C. Nieh et al. reported an unusual superplasticity, more precisely, superplastic-like behavior that had not been discovered with earlier experimental results. The objectives of this work is to obtain an optimum condition for hot working of a 2124Al/15%SiC[sub w] and to suggest a model which can qualitatively explain the extended ductility in the two-phase(solid and liquid phases) region.