The Effect of Heat Treatments on Microstructure and Creep Properties of Powder Metallurgy Beta Gamma Titanium Aluminide Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 500-503 ◽  
Author(s):  
Trevor Sawatzky ◽  
Dong Yi Seo ◽  
H. Saari ◽  
D. Laurin ◽  
Dae Jin Kim ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Titanium Aluminide ◽  
Room Temperature ◽  
Tensile Creep ◽  
Air Cooling ◽  
Gamma Titanium Aluminide ◽  
Creep Properties ◽  
Gamma Titanium ◽  
Titanium Aluminide Alloys ◽  
Lamellar Interfaces

The microstructure and creep properties of two powder metallurgy (PM) ‘beta gamma’ titanium aluminide alloys are presented. Alloy powders with nominal compositions of TiAl-4Nb-3Mn (G1) and TiAl-2Nb-2Mo (G2) were produced by gas atomization and consolidated by a two-step hot isostatic pressing (HIP) process (1250 °C/200 MPa/1 hour + 1100 °C/200 MPa/3 hours + slow cooling to room temperature). After HIP, the materials were given a step cooled heat treatment (SCHT) of 40 min at 1400 °C, furnace cooling to 1280 °C, and air cooling to room temperature. Selected specimens were aged at 900 °C for 6 or 24 hours. The SCHT yielded similar fully lamellar microstructures for both alloys, with a lamellar spacing of 0.04 m, but with different grain sizes averaging 80 m (G1) and 40 m (G2). The aging treatments generated  precipitates along lamellar colony boundaries in both alloys, but along lamellar interfaces only in alloy G2. Constant load tensile creep tests were performed at 760 °C and 276 MPa. Alloy G2 exhibited superior creep performance compared to alloy G1, due to the quantity and size of  precipitate particles at the lamellar interfaces.

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.

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.

Recent Advances in Gamma Titanium Aluminide Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Young-Won (Y-W.) Kim
Keyword(s):  
Titanium Aluminide ◽  
Thin Plates ◽  
Second Phase ◽  
Two Phase ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
The Matrix ◽  
Evolution Of Microstructure ◽  
Titanium Aluminide Alloys ◽  
Extended Discussion

ABSTRACTGamma titanium aluminide alloys of current interest are two-phase alloys consisting of γ-TiAl phase as the matrix and a α2-Ti3Al phase as the second phase. The properties of these alloys depend on alloy composition, processing, microstructure, and their combination. Two major microstructural constituents are gamma grains and lamellar grains, the latter of which contain alternate layers of gamma (γ) and alpha-2 (α2) thin plates. The relative amounts and distribution of these two constituents are the main factors controlling mechanical properties. This paper reviews our current understanding of the composition/microstructure/property relationships. An extended discussion will be made on the fundamental aspects of the formation of lamellar structure during cooling and the evolution of microstructure occurring during thermomechanical treatments.

Sign in / Sign up

Export Citation Format

Share Document