Al—Mn二十面体准晶相的形态观察

用扫描电镜和透射电镜以熔态单辊急冷的Ａｌ－Ｍｎ条带炽的二十面体准晶相的形态进行观察，发现在冷却速度高的与辊筒面接触的区域，准晶相形态呈“花”状，而在远离接触面的区域，则呈较规则的枝晶状，两种形态的准晶似乎都是在量亚晶粒的相互聚集由于先形成的准晶中心核处向外生长，由于成核密度的差异，枝晶状准晶的尺寸是“花”状准晶的数倍。

MORPHOLOGY OBSERVATION OF Al-Mn ICOSAHEDRAL QUASICRYSTAL

The morphology of icosahedral quasicrystals in the Al-Mn ribbon rapidly quenched from the melt by single-roll method had been observed by SEM and TEM. In the region near the roll-contacting side, because of higher cooling rate, the quasicrystals appear as flower-like, while in the region near air-contacting side they appear as regular dendrites due to relative lower cooling rate. The quasicrystal in both cases seems to grow from the center by aggregation of many sub-grains. The nucleation density of the flower-like quasicrystal is obviously higher than that of dendritic one, resulted in the difference of quasicrystal size.