Abstract:

With Zn as the primary alloying addition, alloy from the 7000 family offers higher tensile strength than many steel especially in T6 temper. These family are widely employed for aircraft, wheels and major structural components, due to its high strength-to-density ratio. Semisolid forming has many advantages such as able to produce high density material, long tool life, less production forge and near net shape. Also less liquid fraction then cast, results as less shrinkage. Semi-solid products are more durable then cast ones because of non-dendritic microstructure and less porosity, also cheaper than both cast and forged products. ECAP is an operation that involves simple shear deformation by severe plastic deformation processes. However, the material will not be subjected to any cross sectional changes. No cross sectional changing is the most important feature that distinguishes it from conventional methods. In this study, one of the most important wrought alloys for aerospace applications, AA7075 was used. In order to get the best semi-solid forming feedstock, thixotrophic character has been determined in terms of predeformation rate, heating temperature and holding time.

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