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The traditional solution treatment cycles that are currently applied to rheo-processed A201 are mostly those that are used for conventional castings. These solution treatments are not necessarily the optimum solution treatments for rheo-processing. As a result, DSC analysis was done to optimize this heat treatment. The new solution treatment, which consists of higher temperatures and shorter times (515°C/5h, followed by 570°C/10h), resulted in slightly higher hardness values for both alloy A206 and A201.

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Semi-solid metal processing results in liquid segregation at the surface of the components. The pitting behavior of this surface layer of semi-solid metal processed alloy F357 was compared with the centre (or bulk) of cast plates in 3.5% NaCl aqueous solution. It is shown that pitting attack occurs preferentially in the eutectic regions at the interface between silicon particles and the alpha phase in the eutectic. Since the surface liquid segregation layer consists of mainly eutectic, this makes semi-solid metal processed components specially susceptible to pitting corrosion attack.

Rheocasting of alloys A206 and A201 was investigated in this study. Conical bars with different silver contents were produced using CSIR rheoprocess technology, together with high pressure die casting. The results showed that addition of Ag to alloy A206 increased the mechanical properties of the alloy. However, the addition of Ag also resulted in Cu-rich phases to precipitate at the grain boundaries of the as-cast material. The solution treatment used in this study was unable to dissolve all of this phase, especially in the 1.12%Ag-containing alloy. This resulted in slightly decreased mechanical properties compared to the 0.63%Ag-containing alloy. The T6 mechanical properties (strength and elongation) obtained in this study for rheocast A206 and A201 are better than those reported for permanent mould castings of alloy A206 and A201.