Fe68Si32合金液态结构与固态组织的相关性

利用液态X射线衍射仪研究了Fe68Si32合金的液态结构，获得了结构因子、径向分布函数、原子间的最近邻距离和配位数.结果表明，在1250～1450 ℃范围内液态合金的最近邻距离为0.259～0.260 nm，配位数为10.3(±0.2)；液态合金的结构因子在Q=15.5 nm－1处有一明显的预峰存在.根据预峰的特性，建立了Fe68Si32熔体的结构模型，即体心立方结构的有序Fe3Si原子团以共面的方式形成Fe3Si面心立方超结构(DO3)；合金在1250 ℃的径向分布函数的Gauss分解结果与合金的面心立方模型吻合较好.预峰的产生是面心立方超结构原子团中Si原子之间相互关联的外在表现. Fe68Si32合金的固态X射线衍射显示合金中含有Fe3Si相，而且其特征峰与合金的结构因子的峰位基本一致，表明Fe68Si32合金的液固态结构之间联系紧密.

Correlation between Liquid and Soli d Structure of Fe_(68)Si_(32) Allogy

Using high temperature θ θ X ray diffractometer,the liquid structure of Fe68Si32 alloy was investigated and the structure factor, radial distribution function, the nearest neighbor distance and coordination number were obtained. In the temperature range of 1250～1450 ℃ the nearest neighbor distance and coordination number of the alloy are 0.259～0.260 nm and 10.3(±0.2), respectively. A visible pre peak atQ=15.5 nm－1 in the structure factor S(Q) of liquid Fe68Si32 alloy is observed. According to the characters of pre peak, an atom model of liquid Fe68Si32 alloy was constructed, namely, ordered bcc Fe3Si clusters form a Fe3Si fcc superstructure unit(DO3) with a shared face. The results of Gaussian separation of RDF for Fe68Si32 alloy at 1250 ℃ agrees well with that of Fe3Si superstructure. The pre peak is related to the correlation between silicon atoms in the superstructure. The X ray diffraction of solid Fe68Si32 alloy showed the existence of Fe3Si phase in the alloy and the peaks agree with that of S(Q), which means the correlation of structure between liquid and solid Fe68Si32 alloy.