Abstract
The local atomic structure near an Nb atom in
a Ti–20 at. %Nb alloy single crystal, which
consists of the β, α′′ and ω
Ti phases, was investigated by means of X-ray fluorescence
holography (XFH). The atomic images were reconstructed in the vicinity
of an Nb atom, which is one of the typical β stabilizing
elements in β Ti alloys. Most atoms in the β
Ti primary phase were reconstructed clearly. The atoms in the
α′′ Ti martensite phase could not be
reconstructed, because the α′′ Ti
martensite has the crystal structure with low symmetry. Some atoms in
the ω Ti fine precipitates were reconstructed
successfully, although the amount of the ω Ti phase was
much smaller than that of the β phase. An Nb atom and its
first nearest neighbors tend to keep the BCC structure even upon the
ω Ti phase formation.
摘要
利用X射线荧光全息术(XFH)研究了由β、α′′和ω Ti相组成的Ti-20 at. %Nb合金单晶中Nb原子附近的局部原子结构。在Nb原子附近重建了原子图像,Nb是β Ti合金中典型的β稳定元素之一。大多数β Ti初生相中的原子被清晰地重建了。α′′ Ti马氏体相中的原子无法被重建,因为α′′ Ti马氏体具有低对称性的晶体结构。ω Ti细小沉淀中的一些原子被成功地重建,尽管ω Ti相的数量要比β相小得多。Nb原子及其最近邻原子倾向于在ω Ti相形成时保持BCC结构。