Modeling of the uniaxial tensile and compression behavior of semi-solid A356 alloys

Uniaxial tensile and compressive tests with the industrial aluminium alloy A356 were carried out at various temperatures in the semi-solid regime to determine the constitutive behavior of the alloy during the solidification in casting processes. The experimental findings show a pronounced strength difference in compression and tension as a function of the solid volume fraction. The semi-solid alloy is modeled on the macroscale as a visco-plastic porous medium saturated with liquid. A generalized creep law is modified to take into account the geometry of the pore space, the coherency of the dendrites and the response of the material to the different loading directions. This provides a continuous description of the constitutive behavior of the semi-solid alloy from the coherency temperature to the creep regime of the fully solidified state.