EVOLUTION OF FOAMING IN Al-SI THROUGH THE SEMISOLID STATE

摘要

Aluminum foams with high levels of porosity have become a class of high strength-to-weight ratio materials that will be used in automobile and building industries. In this study, the foaming of Al-7Si samples was interrupted at different temperatures in the semisolid state. The influence of processing parameters such as foaming temperature and time on the cellular structural performance of the material is investigated. For aluminum foams produced in the semisolid state, the existence of solid grains increases the effective viscosity of the melt that plays an important role in bubble formation. The mechanisms of bubble nucleation, growth, coarsening, coalescence and drainage are discussed.