| It has been already known that the addition of several refining elements had the refining effect of primary silicon crystals in high silicon-aluminum alloy. However, the effect of Cu addition has not yet been studied. The purpose of this study is to clarify effects of an amount of Cu added, pouring temperatures, holding time and the double treatment with S on the refinement of primary silicon crystals in an Al-20% Si alloy. Influences on primary silicon crystals by Cu addition observed with metallographic examinations and X-ray diffraction methode. The results obtained are as follows: 1) With the addition of Cu, the finest primary silicon crystals is high silicon-Al alloys were obtained with 0.6% at 750℃ and, 1% at 800℃ and 850℃. 2) The refining effect increased significantly for first five minutes period after the treatment. However, the longer holding did not improve a refining effect. 3) The refining effect of the double treatment with S was better than the single treatment by Cu |
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