抄録
Two-step aging behavior of an Al–10%Si–0.3%Mg alloy cast into permanent mold, rolled up to 68% and solution-treated was investigated by micro-vickers hardness measurement and transmission electron microscopy (TEM). In the case that final-aging temperature is relatively lower and the holding time in iced water is longer, negative effect of two-step aging was observed because the peak hardness in the final-aging stage was slightly decreased. Similar tendency was obtained in the case that the pre-aging temperature is increased to room temperature. On the other hand, pre-aging at 423 K for a relatively long time slightly increased the peak hardness in the final-aging stage with a shorter time to reach the peak hardness. Such a two-step aging behavior is considered due to the influence of precipitated phases such as clusters, G.P. zones, parallelogram-type and β″ in the matrix.
