In Situ Study of γ-TiAl Lamellae Formation in Supersaturated α2-Ti3Al Grains

被引：11

作者：

Cha, Limei ^{[1
,2
]}

Schmoelzer, Thomas ^{[1
]}

Zhang, Zaoli ^{[3
]}

Mayer, Svea ^{[1
]}

Clemens, Helmut ^{[1
]}

Staron, Peter ^{[4
]}

Dehm, Gerhard ^{[3
,5
]}

机构：

[1] Univ Leoben, Dept Phys Met & Mat Testing, A-8700 Leoben, Austria

[2] Mat Ctr Leoben Forsch GmbH, A-8700 Leoben, Austria

[3] Austrian Acad Sci, Erich Schmid Inst Mat Sci, A-8700 Leoben, Austria

[4] Helmholtz Zentrum Geesthacht, Inst Mat Res, D-21502 Geesthacht, Germany

[5] Univ Leoben, Dept Mat Phys, A-8700 Leoben, Austria

来源：

ADVANCED ENGINEERING MATERIALS | 2012年 / 14卷 / 05期

关键词：

MICROSTRUCTURE; DIFFUSION;

D O I：

10.1002/adem.201100272

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

In situ heating transmission electron microscopy (TEM) was used to investigate the initial stage of gamma-TiAl lamellae formation in an intermetallic Ti45Al7.5Nb alloy (in at.%). The material was heat treated and quenched in a non-equilibrium state to consist mainly of supersaturated, ordered a2-Ti3Al grains. Subsequently, specimens were annealed inside a TEM up to 750 degrees C. The in situ TEM study revealed that ultra-fine gamma-TiAl laths precipitate in the a2-matrix at approximate to 730 degrees C which exhibit the classical Blackburn orientation relationship, i.e. (0001 alpha 2//(111)gamma and [$11{\bar {2}}0$]alpha 2//<110]gamma. 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 ?-phase with a complementary method, in situ high energy X-ray diffraction experiments were performed which confirmed the finding that gamma-laths start to precipitate at approximate to 730 degrees C from the supersaturated a2-matrix.

引用

页码：299 / 303

页数：5

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