Journal Article

PUBDB-2015-03594

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Evolution of the $\omega$${_o}$ phase in a $\beta$-stabilized multi-phase TiAl alloy and its effect on hardness

Schloffer, M.>Extern* ; Rashkova, B. ; Schöberl, T. ; Schwaighofer, E.>Extern* ; Zhang, Z. ; Clemens, H.>Extern* ; Mayer, S. (Corresponding author)>Extern*

2014
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.actamat.2013.10.036

Abstract: The intermetallic b-stabilized Ti–43.5Al–4Nb–1Mo–0.1B alloy (in at.%), termed TNM alloy, is designed to be used at elevated temperatures,typically up to 750 C. To understand the evolution of the microstructures during heat treatments and subsequent creep tests,an understanding of the phase transformations and decomposition reactions that occur is necessary. The present study deals with thedevelopment and growth mechanism of the ω${_o}$ phase, which forms in the b${_o}$ phase during static annealing treatments and creep testsperformed at 750, 780 and 800 C using an applied stress of 150 MPa. In situ high-energy X-ray diffraction experiments were conducted to investigate the decomposition behaviour of the ω${_o}$ phase during heating as well as to determine its dissolution temperature. Highresolutiontransmission electron microscopy was used to study the coarsening of xo grains during creep. The chemical compositionof b${_o}$ and ω${_o}$ was determined by means of energy dispersive X-ray microanalysis. In particular, the impact of the Mo content on thegrowth of the ω${_o}$ grains within the b${_o}$ matrix was investigated. Additionally, nanohardness measurements in c, a${_2}$, b${_o}$ and (b${_o}$ + ω${_o}$) grainswere performed by cube corner indentation. The results show that b${_o}$ is the hardest phase in the TiAl–Nb–Mo alloy system when finelydispersed xo precipitates are present.

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Contributing Institute(s):

1. Zentrum für Material- und Küstenforschung (HZG)

Research Program(s):

1. 6G3 - PETRA III (POF3-622) (POF3-622)
2. PETRA Beamline P07 (POF2-54G14) (POF2-54G14)
3. ELISA - European Light Sources Activities - Synchrotrons and Free Electron Lasers (226716) (226716)

Experiment(s):

1. PETRA Beamline P07 (PETRA III)

Appears in the scientific report 2014

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Database coverage:
; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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