STRUCTURAL TRANSFORMATION AND ITS REVERSIBILITY IN LIQUID Al-13%Si ALLOY AT HIGH TEMPERATURES

ＳＴＲＵＣＴＵＲＡＬＴＲＡＮＳＦＯＲＭＡＴＩＯＮＡＮＤＩＴＳＲＥＶＥＲＳＩＢＩＬＩＴＹＩＮＬＩＱＵＩＤＡｌ１３％ＳｉＡＬＬＯＹＡＴＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＳ①ＷａｎｇＷｅｉｍｉｎ，ＢｉａｎＸｉｕｆａｎｇ，ＱｉｎＪｉｎｇｙｕａｎｄＹｅＹｉｆｕＣ...

Using high temperature Xray diffraction analysis, the liquid structures of Al13%Si alloy at 625～1 250 ℃ on heating and those at 675 ℃ after overheating of various temperatures were presented. It is shown that the atomic density and coordination number of the melt increased slightly at first, then decreased greatly at 775～875 ℃. The liquid structure of the melt at 675 ℃ and the morphology of the solidified alloy had no obvious change after overheating at various temperatures. These results indicate that structural transformation happens in liquid Al13%Si and it is reversible.