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.

The Effects of Hot Isostatic Pressing Conditions on the Microstructure of Beta-Gamma Titanium Aluminide Powder Alloys

2010 ◽  
Vol 89-91 ◽  
pp. 325-330
Author(s):  
D. Laurin ◽  
Dong Yi Seo ◽  
H. Saari ◽  
Young Won Kim
Keyword(s):  
Titanium Aluminide ◽  
Volume Fraction ◽  
Hot Isostatic Pressing ◽  
Beta Phase ◽  
Hot Workability ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Isostatic Pressing ◽  
Powder Alloys ◽  
Titanium Aluminide Alloys

The effects of hot isostatic pressing temperature and cooling rate on the microstructure of two powder metallurgy beta-gamma titanium aluminide alloys with nominal compositions TiAl 4Nb 3Mn (G1) and TiAl-2Nb-2Mo (G2) are investigated. Particular attention is placed on the volume fraction of the beta phase, which is known to improve the hot workability. The alloys are consolidated by hot isostatic pressing at 1200 °C, 1250 °C, and 1300 °C, and cooled at rates between 3.0 °C/min and 17.5 °C/min. The volume fraction of beta phase in both alloys was unaffected by the change in cooling rates. The volume fraction of the beta phase in G2 decreased linearly from ~9.5 vol.% to ~3.5 vol.% with increasing HIP temperature from 1200 °C to 1300 °C.

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.

Investment Casting of Near-Net Shape Gamma Titanium Aluminide Automotive Turbocharger Rotor

2005 ◽  
Vol 475-479 ◽  
pp. 2547-2550 ◽  
Author(s):  
Myoung Gyun Kim ◽  
Si Young Sung ◽  
Gyu Chang Lee ◽  
Joon Pyo Park ◽  
Young Jig Kim
Keyword(s):  
Numerical Simulation ◽  
Titanium Aluminide ◽  
Defect Formation ◽  
Centrifugal Casting ◽  
Casting Process ◽  
Metal Mold ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Near Net Shape ◽  
Casting Design

The objective of this study was to optimize the casting design of gamma titanium aluminde automotive turbocharger rotor by means of the practical experiment and numerical simulation. Gamma titanium aluminide rotors were produced by centrifugal casting methods on a laboratory scale. Based on the metal-mold reaction of gamma titanium aluminide, the investment molds were manufactured by an electro-fused Al2O3 mold. The experimental results showed that the castings failed to reach the end of the cavities due to insufficient centrifugal force and a lower fluidity compared to the other metals. Although the satisfactory results were not obtained in the numerical simulation, it was concluded that numerical simulation aided to achieve understanding of the casting process and defect formation in gamma titanium aluminide turbocharger rotor castings.

Microstructural Characterization of Al2O3/Gamma Titanium Aluminide Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
G. Das ◽  
S. Krishnamurthy
Keyword(s):  
Electron Microscopy ◽  
Titanium Aluminide ◽  
Hot Isostatic Pressing ◽  
Microstructural Characterization ◽  
Matrix Interface ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Matrix Microstructure ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

ABSTRACTAlumina (A12O3) fibers were incorporated into gamma titanium aluminide(TiAl) based powders by hot isostatic pressing (HIP'ing). The microstructure of as-HIP'd and heat treated composite specimens were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TEM studies reveal the presence of an amorphous reaction zone at the fiber/matrix interface. Numerous dislocations, dipoles and loops as well as twins are observed in A12O3 fibers. In addition, it is determined that the fiber/matrix interface stability is significantly affected by the matrix microstructure.

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