The Dependence of Tensile Ductility on Investment Casting Parameters in Gamma Titanium Aluminides

1998 ◽  
Vol 552 ◽  
Author(s):  
R. Raban ◽  
L. L. ◽  
T. M.
Keyword(s):  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Tensile Ductility ◽  
Gamma Titanium Aluminide ◽  
Cooling Rates ◽  
Gamma Titanium ◽  
Investment Cast ◽  
Thermal Data ◽  
Titanium Aluminide Alloys ◽  
Simulation Package

ABSTRACTPlates of three gamma titanium aluminide alloys have been investment cast with a wide variety of casting conditions designed to influence cooling rates. These alloys include Ti-48Al-2Cr-2Nb, Ti- 47Al-2Cr-2Nb+0.5at%B and Ti-45Al-2Cr-2Nb+0.9at%B. Cooling rates have been estimated with the use of thermal data from casting experiments, along with the UES ProCAST simulation package. Variations in cooling rate significantly influenced the microstructure and tensile properties of all three alloys.

Comparison of the electrochemical machinability of electron beam melted and casted gamma titanium aluminide TNB-V5

2017 ◽  
Vol 232 (4) ◽  
pp. 586-592 ◽  
Author(s):  
Fritz Klocke ◽  
Tim Herrig ◽  
Markus Zeis ◽  
Andreas Klink
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Current Density ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Electrochemical Machining ◽  
Dissolution Behavior ◽  
Removal Rates ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium

Additive manufacturing technologies are becoming more and more important for the implementation of efficient process chains. Due to the possibility of a near net shape, manufacturing time for finish-machining can significantly be reduced. Especially for conventionally hard to machine materials like gamma titanium aluminides (γ-TiAl), this manufacturing process is very attractive. Nevertheless, for most applications, a rework of these generative components is necessary. Independently of the mechanical material properties, electrochemical machining is one promising technology of machining these materials. Major advantages of electrochemical machining are its process-specific characteristics of high material removal rates in combination with almost no tool wear. But electrochemical machining results are highly dependent on the microstructure of the material regarding the surface roughness. Therefore, this article deals with research on electrochemical machining of electron beam melted γ-TiAl TNB-V5 compared to a casted form of this alloy. The difference between the specific removal rates as a function of current density is investigated using electrolytes based on sodium nitrate and sodium chloride. Moreover, the dissolving behavior of the electron beam melted and casted structure is analyzed by potentiostatic polarization curves. The surface roughness is heavily dependent on a homogeneous dissolution behavior of the microstructure. Thus, the mean roughness as a function of current density is investigated as well as rim zone analyses of the different structures.

Studies on Ductile Damage and Flow Instabilities during Hot Deformation of a Multiphase γ-TiAl Alloy

2014 ◽  
Vol 611-612 ◽  
pp. 99-105 ◽  
Author(s):  
Dilek Halici ◽  
Hassan Adrian Zamani ◽  
Daniel Prodinger ◽  
Cecilia Poletti ◽  
Daniel Huber ◽  
...  
Keyword(s):  
Hot Deformation ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Shear Bands ◽  
Flow Instabilities ◽  
Ductile Damage ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Damage Models

Gamma titanium aluminides are promising alloys for low-pressure turbine blades. A significant disadvantage of such intermetallic alloys is failure induced during forming processes due to ductile damage and flow instabilities. Previous investigations on a gamma titanium aluminide alloy (TNM), have shown ductile damage due to tensile stress components and instabilities such as shear bands, pores and micro-cracks at low temperatures and high strain rates. The main part of the current work is to delineate damage and unstable regions in the low temperature region. Hot deformation experiments are conducted on a Gleeble®3800 thermomechanical treatment simulator to obtain flow curves to be implemented in a finite element method (FEM) code. Instabilities in the material are described by existing instability criteria as proposed by Semiatin and Jonas and implemented into FEM code DEFORMTM 2D. Predictions of ductile damage models and the instability parameter are validated through detailed microstructural studies of deformed specimens analysed by light optical- and scanning electron microscopy.

scholarly journals Advancement of Plasma Cold-Hearth Melting for Production of Gamma Titanium Aluminide Alloys within Arconic

2020 ◽  
Vol 321 ◽  
pp. 08008
Author(s):  
Ernie Crist ◽  
Birendra Jena ◽  
Michael Jacques ◽  
Matt Dahar ◽  
Don Li ◽  
...  
Keyword(s):  
Titanium Aluminide ◽  
Centrifugal Casting ◽  
Hot Isostatic Pressing ◽  
Industrial Applications ◽  
Vacuum Arc ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Arc Melting ◽  
The Impact ◽  
Titanium Aluminide Alloys

Utilization of gamma titanium aluminide alloys in aerospace and automotive/industrial applications has placed significant demand on melting sources for products to be used in cast, wrought, and direct-machining applications. There is also an increased demand for input stock used in gas atomization of powders. Current technologies used in ingot manufacturing include plasma arc melting, vacuum arc melting, and induction skull melting + centrifugal casting. Subsequent processing may include forging, re-melting + casting, or machining directly into components. Over the past six years, Arconic Engineered Structures has developed a robust melting method using plasma cold-hearth melting technology, including the design and implementation of a new 3-torch system to produce Ti-48-2-2 cast bars. General discussions concerning plasma cold-hearth melting, manufacturing challenges, and metallurgical attributes associated with cast Ti-48-2-2 bars will be reviewed. Emphasis will be on understanding the impact of hot isostatic pressing on internal voids, residual stress cracking and resulting mechanical properties.

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