Experimental characterisation of a semi-solid A356 alloy during solidification and remelting

Within the general framework of hot tearing research in casting processes the tensile behaviour of the semi-solid aluminium alloy A356 under remelting and solidification conditions is studied. In order to measure true-stress versus true-strain curves of the semi-solid metal, a new experimental technique has been developed to perform hot tensile tests in the mushy regime between the coherency and the solidus temperatures. The local true-strain in the semi-solid region of the tensile specimen is measured optically with a laser speckle extensometer (LSE). During the solidification tests measurement is done by using a transparent aero-gel mould. The resulting stress-strain curves and the corresponding microstructure are compared for the remelting and solidification condition.