Texture evolution with superplastic deformation of a AlCu4Mg/Si3N4/20p composite

The deformation mechanisms which operate during superplastic tensile deformation at 783 K in a AlCu4Mg/Si3N4/20p composite have been investigated by means of the crystallographic texture evolution with strain. Three stages of texture evolution have been observed: in stage I, little texture variation occurs up to a true strain of 0.4. In stage II, a progressive decrease of texture intensity up to a true strain of 0.8 is noted. This suggests that a mechanism of grain boundary sliding, GBS, typical of superplastic deformation of monolithic fine grained polycrystalline materials, prevails in this stage. At higher deformations, in stage III, the intensity of the main texture components tends to increase, indicating that the dominant deformation mechanism becomes crystallographic slip, CS.