scholarly journals Development of TiAl–Si Alloys—A Review

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1030
Author(s):  
Anna Knaislová ◽  
Pavel Novák ◽  
Marcello Cabibbo ◽  
Lucyna Jaworska ◽  
Dalibor Vojtěch
Keyword(s):  
Titanium Aluminide ◽  
Room Temperature ◽  
High Hardness ◽  
Tool Steels ◽  
Good Resistance ◽  
Intermetallic Materials ◽  
Room Temperature Ductility ◽  
Resistance To Oxidation ◽  
Process Structure ◽  
Titanium Aluminide Alloys

This paper describes the effect of silicon on the manufacturing process, structure, phase composition, and selected properties of titanium aluminide alloys. The experimental generation of TiAl–Si alloys is composed of titanium aluminide (TiAl, Ti3Al or TiAl3) matrix reinforced by hard and heat-resistant titanium silicides (especially Ti5Si3). The alloys are characterized by wear resistance comparable with tool steels, high hardness, and very good resistance to oxidation at high temperatures (up to 1000 °C), but also low room-temperature ductility, as is typical also for other intermetallic materials. These alloys had been successfully prepared by the means of powder metallurgical routes and melting metallurgy methods.

Dispersoid Modification of Ti3Al-Nb Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
R. G. Rowe ◽  
J. A. Sutliff ◽  
E. F. Koch
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Titanium Aluminide ◽  
Melt Spinning ◽  
Room Temperature ◽  
Beta Transus ◽  
Processing Conditions ◽  
Room Temperature Ductility ◽  
Rapidly Solidified ◽  
Titanium Aluminide Alloys

ABSTRACTTitanium aluminide alloys with matrix compositions of essentially Ti3Al plus 0, 5, 7.5, and 10 a/o Nb and with and without rare earth elements for dispersoid formation were prepared. The alloys were rapidly solidified by melt spinning. Ribbon was consolidated by HIP and extrusion at temperatures below the beta transus temperatures of the alloys. The effects of processing conditions and dispersoid additions on room temperature ductility and fracture toughness were studied.

scholarly journals Resistance of WE43 and ZRE1 Magnesium Alloys to Gas Corrosion

2017 ◽  
Vol 17 (2) ◽  
pp. 217-221
Author(s):  
R. Przeliorz ◽  
J. Piątkowski
Keyword(s):  
Magnesium Alloys ◽  
Oxidation Rate ◽  
Room Temperature ◽  
Good Resistance ◽  
Magnesium Matrix ◽  
Protective Properties ◽  
Resistance To Oxidation ◽  
Plastic Forming ◽  
Foundry Alloys ◽  
Gas Corrosion

AbstractIn spite of the fact that in most applications, magnesium alloys are intended for operation in environments with room temperature, these alloys are subject to elevated temperature and oxidizing atmosphere in various stages of preparation (casting, welding, thermal treatment). At present, the studies focus on development of alloys with magnesium matrix, intended for plastic forming. The paper presents results of studies on oxidation rate of WE43 and ZRE1 magnesium foundry alloys in dry and humidified atmosphere of N2+1%O2. Measurements of the oxidation rate were carried out using a Setaram thermobalance in the temperature range of 350-480°C. Corrosion products were analyzed by SEM-SEI, BSE and EDS. It was found that the oxide layer on the WE43 alloy has a very good resistance to oxidation. The high protective properties of the layer should be attributed to the presence of yttrium in this alloy. On the other hand, a porous, two-layer scale with a low adhesion to the substrate forms on the ZRE1 alloy. The increase in the sample mass in dry gas is lower than that in humidified gas.

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.

scholarly journals A Review of Milling of Gamma Titanium Aluminides

2018 ◽  
Vol 3 (2) ◽  
pp. 1-9
Author(s):  
S. Castellanos ◽  
J. Lino Alves
Keyword(s):  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Chemical Reactivity ◽  
Cutting Tools ◽  
High Hardness ◽  
High Strength ◽  
Milling Process ◽  
Current Trends ◽  
Corrosive Environments ◽  
Titanium Aluminide Alloys

Intermetallic titanium aluminide alloys are used in the high technology engineering field with the goal of achieving weight reduction in different components, exposed to corrosive environments and high temperatures in aeronautical and automotive industries. Despite their attractive properties such as low density, high strength, high stiffness and good corrosion, creep and oxidation resistance, the machinability of titanium aluminide alloys is difficult due to its high hardness, chemical reactivity, and low ductility. This article reviews the state of the art regarding the machinability of titanium aluminide alloys and focuses on the analysis of the milling process, namely the process parameters, surface integrity and cutting tools. The influence of titanium aluminides properties on the machinability is also discussed presenting some current trends and further needed research.

Tensile and Creep Behavior of Ordered Orthorhombic Ti2A1Nb-Based Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
R.G. Rowe ◽  
D.G. Konitzer ◽  
A.P. Woodfield ◽  
J.C. Chesnutt
Keyword(s):  
Heat Treatment ◽  
Titanium Aluminide ◽  
Room Temperature ◽  
Single Phase ◽  
Two Phase ◽  
Creep Properties ◽  
Specific Strength ◽  
Heat Treated ◽  
Titanium Aluminide Alloys

ABSTRACTTitanium aluminide alloys with compositions near Ti-25A1-25Nb at.% were prepared by both rapid solidification and ingot techniques. Their tensile and creep properties were studied after heat treatment to produce various microstructures containing ordered orthorhombic (O) [1], ordered beta (βo), and α2 phases. It was found that these alloys had higher specific strength from room temperature to 760°C than conventional α2 alloys. Ductility and tensile strength of O+βo alloys were strongly dependent upon heat treatment, with the highest strength observed as-heat-treated, and the highest ductility after long term aging. The creep resistance of single phase O and two phase O+βo alloys was strongly dependent upon heat treatment.

Effect of Superplastic Processing on Room Temperature Ductility of Gamma Titanium Aluminide

1996 ◽  
Vol 243-245 ◽  
pp. 637-642
Author(s):  
Renat M. Imayev ◽  
Gennady A. Salishchev ◽  
V.M. Imayev ◽  
M.R. Shagiev
Keyword(s):  
Titanium Aluminide ◽  
Room Temperature ◽  
Gamma Titanium Aluminide ◽  
Gamma Titanium ◽  
Room Temperature Ductility

Hydrogen-induced phase transformations in α2+B2 Ti-25Al-10Nb-3V-lMo titanium aluminide

1995 ◽  
Vol 53 ◽  
pp. 520-521
Author(s):  
X. Pierron ◽  
M. De Graef ◽  
T.M. Pollock ◽  
A.W. Thompson
Keyword(s):  
Group Theory ◽  
Hydrogen Embrittlement ◽  
Titanium Aluminide ◽  
Room Temperature ◽  
Martensitic Transformations ◽  
Phenomenological Theory ◽  
Ti Alloys ◽  
Free Cooling ◽  
Second Phases ◽  
Titanium Aluminide Alloys

Titanium aluminide alloys containing the DO19α2 (Ti3Al) phase, such as Ti-25Al-10Nb-3V-1Mo (at.%), are known to be sensitive to hydrogen. Such alloys could provide an alternative for conventional Ti alloys in a hydrogen-rich environment, and an understanding of the hydrogen embrittlement mechanisms acting in these materials is needed. Hydrides are known to form in conventional Ti alloys. Hence, a systematic study was undertaken to investigate the possibility of hydrogen-induced second phases in the Ti-25Al-10Nb-3V-1Mo alloy. We report here that internal hydrogen results in the precipitation of an orthorhombic OH phase in the α2 grains. The morphology and the orientations of the orthorhombic variants can be successfully described using group theory and the phenomenological theory of martensitic transformations.The as-received material consisted of bars extruded in the (α2 + β) phase field at 1037°C, then oil quenched. A solutionizing treatment at 1085°C, followed by free cooling at 0.1°C/s to room temperature resulted in a microstructure containing primary α2 grains and α2 secondary laths in a B2 matrix.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

ALCHEMI of B2-Ordered Fe50Al45Me5 alloys

1996 ◽  
Vol 54 ◽  
pp. 548-549
Author(s):  
Ian M. Anderson
Keyword(s):  
Room Temperature ◽  
Iron Aluminide ◽  
Low Density ◽  
Intermetallic Alloys ◽  
Practical Applications ◽  
Alloying Additions ◽  
Site Distribution ◽  
Good Corrosion Resistance ◽  
Room Temperature Ductility ◽  
The Matrix

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.

UNS N09706

Alloy Digest ◽  
1989 ◽  
Vol 38 (2) ◽  
Keyword(s):  
High Strength ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Good Resistance ◽  
Nickel Iron ◽  
Temperature Performance ◽  
Resistance To Oxidation ◽  
Oxidation And Corrosion ◽  
Iron Chromium Alloy ◽  
Iron Chromium

Abstract UNS N09706 is a precipitation-hardenable, nickel-iron-chromium alloy with high strength at temperatures to 1200 F and with good resistance to oxidation and corrosion over a broad range of temperatures and environments. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-368. Producer or source: Nickel and nickel alloy producers.

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