Agus Hadi Santosa Wargadipura
Pusat Pengkajian dan Penerapan Teknologi Material, Gedung II BPPT, Jl. MH. Thamrin 8, Jakarta 10340
Abstract
Superplastic deformation is characterized by low flow stresses and combined with the high uniformity of plastic flow. Superplasticity is shown by materials with a fine grain size, when they are deformed in tension within the strain rate range 10^-5 to 10^-2 per second at temperatures greater than a half of its mrlting point, could undergo a very large percentage of tensile deformation without failure. This paper discusses post-forming behavior of the aluminium 7475 sheet after it is superplastically formed into the hemispherical dome geometry at the temperature of 5150C and within 13 minutes forming period. The metallographic of the superplastically formed thin sheet Aluminium 7475 material has beed carried out, namely the microstructure photography and hardness test, to investigate the deformation takes place at microstructures level. It is shown that during the superplastic deformation, the aluminium 7475 sheet undergoes softening processes and there is no significant changes took place in microstructures level of the material after superplastic forming
