六方Al_(14.2)(Fe,V)_(3.0)Si_(1.3)准晶近似晶体相的电子衍射分析

ELECTRON DIFFRACTION STUDY OF A HEXAGONAL Al_(14.2)(Fe,V)_(3.0)Si_(1.3) APPROXIMANT

利用选区电子衍射和会聚束衍射研究了喷射沉积Ａｌ－Ｆｅ－Ｖ－Ｓｉ合金中一种六方相的晶体结构，其点阵常数为： ａ—２．５２ ｃｍ， ｃ＝１．２６ ｎｍ，空间群为 Ｐ６／ｍｍｍ，该六方相与立方相具有固定取向关系，且 ＥＤＳ分析表明，两相成分相 近．系统对比分析 ＳＡＥＤ花样发现，六方相的某些带轴衍射谱具有立方相的二十面体结构基元表现出的衍射特征，表明六方相也 是一种准晶近似晶体相，其结构构架可能由（Ｆｅ＋Ｖ）和（ＡＩ＋Ｓｉ）双层二十面体结构基元以

The crystal structure of a new hexagonal Al14.2(Fe, V)3.0Si1.3 approximant (a=2.52 nm, c=1.26 nm, P6/mmm) in the spray-cast Al-8.5Fe-1.3V-1.7Si alloy has been determinted by selected--area electron diffraction and convergent beam electron diffraction. The crystallographic orientation relationship and the potential structural interrelationship between the hexagonal approximant and the bee a-Al(Fe, V)Si phase are investigated through a systematic study of the electron diffraction behaviour. The similarly between the icosahedral patterns of the hexagonal and bee phases implies the presence of the double (Fe+V) and (Al+Si) icosahedral clusters in both phases, but with different staking arrangements..