Globularisation of α2 phase in (α2+γ) two-phase lamellar titanium aluminide by thermal cycling

2021 ◽  
pp. 129617
Author(s):  
Nitish Bibhanshu ◽  
Satyam Suwas
2000 ◽  
Vol 652 ◽  
Author(s):  
Fritz Appel ◽  
Michael Oehring

ABSTRACTThe paper presents an electron microscope study of phase transformation and recrystallization in an intermetallic α2(Ti3Al) + γ(TiAl) titanium aluminide alloy, after long-term creep. The mechanisms are closely related to the atomic structure of the α2/γ phase boundaries and are probably driven by a non-equilibrium of the phase composition leading to the dissolution of the α2 phase. The α2 /γ transformation is accompanied by the formation of precipitates, because the γ(TiAl)phase has a significantly lower solubility for interstitial impurities than the α2(Ti3Al) phase.


2008 ◽  
Vol 483-484 ◽  
pp. 551-554 ◽  
Author(s):  
S.R. Dey ◽  
Satyam Suwas ◽  
J.-J. Fundenberger ◽  
J.X. Zou ◽  
T. Grosdidier ◽  
...  

1995 ◽  
Vol 410 ◽  
Author(s):  
Weimin Si ◽  
Michael Dudley ◽  
Pengxing Li ◽  
Renjie Wu

ABSTRACTA ternary titanium aluminide alloy, Ti-46Al-3Cr (at%), was discontinuously reinforced with 5 vol% titanium diboride (TiB2), by an in-situ synthesis technique, resulting in a two phase γ(TiAl) (mainly) and α2(Ti3Al) matrix with randomly dispersed TiB2 particle. Interfaces of TiB2-TiAl were investigated by Analytical Electron Microscopy (AEM) and High Resolution Electron Microscopy (HREM). No consistent crystallographic orientation relationship was observed between TiB2 particle and TiAl matrix, and there was no evidence of alloying elements (such as Cr) segregation or interphase formation at the TiB2-TiAl interface. HREM results indicated that no semi-coherent interface between TiB2 and TiAl has been observed. There existed a thin amorphous layer (0.5 to 1.3 nm) at the TiB2-TiAl interface, which may accommodate the large lattice misfit across the interface and enhance the interfacial bonding.


1996 ◽  
Vol 460 ◽  
Author(s):  
F. Herrouin ◽  
P. Bowen ◽  
I. P. Jones

ABSTRACTA complex two phase γ-TiAl alloy, Ti-47Al-lCr-1Mn-2Ta-0.2Si (at.%) in a fully lamellar condition, has been creep tested at a stress of 200MPa and a temperature of 700°C. This simulates the in-service operating conditions for several potential gas turbine aero engine applications where creep resistance is a design limiting material property. The results have indicate that reduction in lamellae thickness and avoidance of feathery type microstructures contribute to improved creep resistance.


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