TY - JOUR
T1 - In situ study of γ-TiAl lamellae formation in supersaturated α 2-Ti 3Al grains
AU - Cha, Limei
AU - Schmoelzer, Thomas
AU - Zhang, Zaoli
AU - Mayer, Svea
AU - Clemens, Helmut
AU - Staron, Peter
AU - Dehm, Gerhard
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/5
Y1 - 2012/5
N2 - In situ heating transmission electron microscopy (TEM) was used to investigate the initial stage of γ-TiAl lamellae formation in an intermetallic Ti-45Al-7.5Nb alloy (in at.%). The material was heat treated and quenched in a non-equilibrium state to consist mainly of supersaturated, ordered α 2-Ti 3Al grains. Subsequently, specimens were annealed inside a TEM up to 750 °C. The in situ TEM study revealed that ultra-fine γ-TiAl laths precipitate in the α 2-matrix at ≈730 °C which exhibit the classical Blackburn orientation relationship, i.e. (0001)α 2//(111)γ and [$112̄0] α 2//<110]γ. The microstructural development observed in the in situ TEM experiment is compared to results from conventional ex situ TEM studies. In order to investigate the precipitation behavior of the γ-phase with a complementary method, in situ high energy X-ray diffraction experiments were performed which confirmed the finding that γ-laths start to precipitate at ≈730 °C from the supersaturated α 2- matrix.
AB - In situ heating transmission electron microscopy (TEM) was used to investigate the initial stage of γ-TiAl lamellae formation in an intermetallic Ti-45Al-7.5Nb alloy (in at.%). The material was heat treated and quenched in a non-equilibrium state to consist mainly of supersaturated, ordered α 2-Ti 3Al grains. Subsequently, specimens were annealed inside a TEM up to 750 °C. The in situ TEM study revealed that ultra-fine γ-TiAl laths precipitate in the α 2-matrix at ≈730 °C which exhibit the classical Blackburn orientation relationship, i.e. (0001)α 2//(111)γ and [$112̄0] α 2//<110]γ. The microstructural development observed in the in situ TEM experiment is compared to results from conventional ex situ TEM studies. In order to investigate the precipitation behavior of the γ-phase with a complementary method, in situ high energy X-ray diffraction experiments were performed which confirmed the finding that γ-laths start to precipitate at ≈730 °C from the supersaturated α 2- matrix.
UR - http://www.scopus.com/inward/record.url?scp=84860825672&partnerID=8YFLogxK
U2 - 10.1002/adem.201100272
DO - 10.1002/adem.201100272
M3 - 文章
AN - SCOPUS:84860825672
VL - 14
SP - 299
EP - 303
JO - Advanced Engineering Materials
JF - Advanced Engineering Materials
SN - 1438-1656
IS - 5
ER -