TY - JOUR
T1 - The origin of striation in the metastable β phase of titanium alloys observed by transmission electron microscopy
AU - Fan, Jiangkun
AU - Li, Jinshan
AU - Zhang, Yudong
AU - Kou, Hongchao
AU - Ghanbaja, Jaafar
AU - Gan, Weimin
AU - Germain, Lionel
AU - Esling, Claude
N1 - Publisher Copyright:
© Jiangkun Fan et al. 2017.
PY - 2017/6
Y1 - 2017/6
N2 - For the β phase of Ti-5553-type metastable β-Ti alloys, striations in transmission electron microscopy (TEM) bright- and dark-field images have been frequently observed but their origin has not been sufficiently investigated. In the present work, this phenomenon is studied in depth from the macroscopic scale by neutron diffraction to the atomic scale by high-resolution TEM. The results reveal that the β phase contains homogeneously distributed modulated structures, intermediate between that of the β phase (cubic) and that of the α phase or the ω phase (hexagonal), giving rise to the appearance of additional diffraction spots at 1/2, 1/3 and 2/3 β diffraction positions. The intermediate structure between β and α is formed by the atomic displacements on each second {110}β plane in the direction, whereas that between β and ω is formed by atomic displacements on each second and third {112}β plane in the opposite direction. Because of these atomic displacements, the {110}β and {112}β planes become faulted, resulting in the streaking of β diffraction spots and the formation of extinction fringes in TEM bright- and dark-field images, the commonly observed striations. The present work reveals the origin of the striations and the intrinsic correlation with the additional electron reflections of the β phase.In the present work, the striations and diffraction characteristics of the β phase of Ti-5553 alloy are thoroughly investigated.
AB - For the β phase of Ti-5553-type metastable β-Ti alloys, striations in transmission electron microscopy (TEM) bright- and dark-field images have been frequently observed but their origin has not been sufficiently investigated. In the present work, this phenomenon is studied in depth from the macroscopic scale by neutron diffraction to the atomic scale by high-resolution TEM. The results reveal that the β phase contains homogeneously distributed modulated structures, intermediate between that of the β phase (cubic) and that of the α phase or the ω phase (hexagonal), giving rise to the appearance of additional diffraction spots at 1/2, 1/3 and 2/3 β diffraction positions. The intermediate structure between β and α is formed by the atomic displacements on each second {110}β plane in the direction, whereas that between β and ω is formed by atomic displacements on each second and third {112}β plane in the opposite direction. Because of these atomic displacements, the {110}β and {112}β planes become faulted, resulting in the streaking of β diffraction spots and the formation of extinction fringes in TEM bright- and dark-field images, the commonly observed striations. The present work reveals the origin of the striations and the intrinsic correlation with the additional electron reflections of the β phase.In the present work, the striations and diffraction characteristics of the β phase of Ti-5553 alloy are thoroughly investigated.
KW - electron diffraction
KW - striation
KW - structure modulation
KW - TEM
KW - Ti alloys
KW - transmission electron microscopy
UR - http://www.scopus.com/inward/record.url?scp=85020231703&partnerID=8YFLogxK
U2 - 10.1107/S1600576717004150
DO - 10.1107/S1600576717004150
M3 - 文章
AN - SCOPUS:85020231703
SN - 0021-8898
VL - 50
SP - 795
EP - 804
JO - Journal of Applied Crystallography
JF - Journal of Applied Crystallography
IS - 3
ER -