The structure of a new ε-phase formed during the early stage of crystallization of Ti-48 AT.% Al amorphous film

被引：11

作者：

Abe, E ^{[1
]}

Ohnuma, M ^{[1
]}

Nakamura, M ^{[1
]}

机构：

[1] Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan

来源：

ACTA MATERIALIA | 1999年 / 47卷 / 13期

关键词：

crystal structure; transmission electron microscopy (TEM); intermetallic compound; sputtering; phase transformations;

D O I：

10.1016/S1359-6454(99)00225-6

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The early stage of crystallization of a Ti-48 at.% Al amorphous thin film has been investigated by transmission electron microscopy (TEM). A novel phase denoted as an epsilon-phase with a cubic lattice of a=0.69 nm was found to precipitate in the amorphous matrix, together with the high-temperature alpha-Ti phase. Chemical analysis by energy-dispersive X-ray spectroscopy revealed that alpha and epsilon-phases have the approximate composition of Ti-48 at.% Al, suggesting an isoconcentrational formation process. The structure of the new epsilon-phase has been determined to be a beta-Mn type (P4(1)32) with atomic sites occupied randomly by Ti and Al atoms, based on close examination of the electron diffraction intensities and the high-resolution TEM image contrasts with the aid of computer simulations. The Ti and Al atoms in this structure are shown to be packed densely according to an icosahedrally close-packed manner. The epsilon-phase is attributed to a metastable phase which could appear at high temperatures in the Ti-Al system. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.

引用

页码：3607 / 3616

页数：10

共 25 条

[1] High-resolution electron microscopy of twin interfaces in massively transformed gamma-TiAl [J].