GROWTH MORPHOLOGIES OF QUASICRYSTALLINE PHASE IN A BULK UNDERCOOLED Al-Mn-(Si,B) ALLOY

ＧＲＯＷＴＨＭＯＲＰＨＯＬＯＧＩＥＳＯＦＱＵＡＳＩＣＲＹＳＴＡＬＬＩＮＥＰＨＡＳＥＩＮＡＢＵＬＫＵＮＤＥＲＣＯＯＬＥＤＡｌＭｎ（Ｓｉ，Ｂ）ＡＬＬＯＹ①ＳｏｎｇＧｕａｎｇｓｈｅｎｇ，ＹａｎｇＧｅｎｃａｎｇａｎｄＺｈｏｕＹａｏｈｅＳｔａｔｅＫｅｙＬａ...

The complex method of glass covering, salt denucleating and multiple superheatingcooling has been successfully applied to undercool the melt of a bulk AlMn(Si,B) alloy and initiate quasicrystalline phase at an undercooling of 100 K. Growth morphologies of the quasicrystalline phase were characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM imagies indicate 5fold and 3fold symmetric faceting dendrites, and dendrite elements and polyhedron particles, respectively. The constitution level and relation to m3 5 point group symmetry of growth morphology for the undercooled quasicrystalline phase have been reported for the first time.