Microstructural design for large superplastic elongations in aluminum-base materials containing particles

The microstructural features (grain size, particle size, and volume fraction of particles) for large superplastic elongations in aluminum-base materials that contain particles were designed from the viewpoint of the superplastic region and the inhibition of cavity nucleation, where the size of the grains is larger than that of the particles and the particles are particulates. These features were derived from the constitutive equations and the local critical stress that inhibits cavity nucleation. The microstructural features derived in this work were compared with those of the various aluminum-base materials containing Si₃N₄ particles. The results indicated these features were comparable. It is concluded that the method for designing microstructural features in this study is effective for large superplastic elongations in aluminum-base materials that contain particles.