Assessing the Influence of Heat Treatments on γ-TiAl Joints

2006 ◽  
Vol 514-516 ◽  
pp. 1333-1337 ◽  
Author(s):  
Anibal Guedes ◽  
Ana Maria Pires Pinto ◽  
Manuel F. Vieira ◽  
Filomena Viana
Keyword(s):  
Titanium Aluminide ◽  
Tial Alloy ◽  
Braze Alloy ◽  
Heat Treating ◽  
Heat Treatments ◽  
Interfacial Zone ◽  
Alloy Foil ◽  
Heat Treated ◽  
Titanium Aluminide Alloy ◽  
Brazed Joints

The heat treatment of γ-TiAl alloy (Ti-47Al-2Cr-2Nb (at.%)) diffusion brazed joints was investigated. Joining was performed using a Ti/Ni/Ti clad-laminated braze alloy foil at 1050 and 1150°C with a dwell time of 10 minutes. The joints were subsequently heat treated at 1250 and 1350°C for 240 and 30 minutes, respectively. The microstructure and the chemical composition of the interfaces were analysed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. Microhardness tests performed across the interface were used to roughly predict the mechanical behaviour of the as-diffusion brazed and of the heat treated joints. Diffusion brazing produced interfaces with two distinct layers essentially composed of α2-Ti3Al and of TiNiAl; γ-TiAl was also detected for joining at 1150°C. After heat treating, the as-diffusion brazed microstructure of the interface was completely replaced by a mixture essentially composed of γ-TiAl and α2–Ti3Al single phase grains and of (α2 + γ) lamellar grains. Microhardness tests showed that the hardness of the as-diffusion brazed interfaces, which ranges from 567 to 844 HV (15 gf), is significantly higher than that of the titanium aluminide alloy (272 HV). All post-joining heat treatments lowered substantially the hardness of the interface, as the hardness of the main phases detected at the interfacial zone after heat treating the joints is comprised between 296 and 414 HV.

Problems Associated with Heat Treated Parts

2021 ◽  
pp. 307-325
Author(s):  
Jon L. Dossett
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Cold Working ◽  
Heat Treating ◽  
Heat Treatments ◽  
Quenching Media ◽  
Heat Treated ◽  
Nonferrous Alloys

Abstract This article introduces some of the general sources of heat treating problems with particular emphasis on problems caused by the actual heat treating process and the significant thermal and transformation stresses within a heat treated part. It addresses the design and material factors that cause a part to fail during heat treatment. The article discusses the problems associated with heating and furnaces, quenching media, quenching stresses, hardenability, tempering, carburizing, carbonitriding, and nitriding as well as potential stainless steel problems and problems associated with nonferrous heat treatments. The processes involved in cold working of certain ferrous and nonferrous alloys are also covered.

Creep Deformation of a Fully Lamellar Gamma Based Titanium Aluminide Alloy

1996 ◽  
Vol 460 ◽  
Author(s):  
F. Herrouin ◽  
P. Bowen ◽  
I. P. Jones
Keyword(s):  
Gas Turbine ◽  
Creep Deformation ◽  
Titanium Aluminide ◽  
Creep Resistance ◽  
Tial Alloy ◽  
Operating Conditions ◽  
Two Phase ◽  
Titanium Aluminide Alloy ◽  
Aero Engine ◽  
Fully Lamellar

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.

scholarly journals Microstructure and Strength of γ-TiAl Alloy/Inconel 718 Brazed Joints

2012 ◽  
Vol 730-732 ◽  
pp. 835-840 ◽  
Author(s):  
Elsa W. Sequeiros ◽  
Anibal Guedes ◽  
Ana Maria Pires Pinto ◽  
Manuel F. Vieira ◽  
Filomena Viana
Keyword(s):  
Inconel 718 ◽  
Tial Alloy ◽  
Electron Backscatter Diffraction ◽  
Braze Alloy ◽  
Base Material ◽  
Industrial Applications ◽  
Processing Conditions ◽  
Average Shear Strength ◽  
Average Shear ◽  
Brazed Joints

Intermetallics and superalloys brazing development is a current topic owing the extending use of these alloys in industrial applications. In this work a γ-TiAl alloy was joined to Inconel 718 by active metal brazing, using Incusil-ABA as filler. Joining was performed at 730 °C, 830 °C and 930 °C, with a 10 min dwelling time. The interfaces were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). For all processing conditions, the reaction between the base materials and the braze alloy produced multilayered interfaces. For all processing temperatures tested (Ag), (Cu), AlNi2Ti and AlCu2Ti were identified at the interface. Raising the brazing temperature increased the thickness of the interface and coarsened its microstructure. The increase of the extension of the interface was essentially due to the growth of the reaction layers formed near each base material, which were found to be mainly composed of intermetallic compounds. The mechanical behavior of the joints, at room temperature, was assessed by microhardness and shear tests. For all processing conditions the hardness decreases from periphery towards the Ag-rich centre of the joints. Brazing at 730 °C for 10 min produced the joints with the highest average shear strength (228±83 MPa). SEM and EDS analysis of the fracture surfaces revealed that fracture of joints always occurred across the interface, preferentially through the hard layer, essentially composed of AlNi2Ti, resulting from the reaction between Inconel 718 and the braze alloy.

Fatigue Properties and Design Criteria of a Gamma Titanium Aluminide Alloy

2011 ◽  
Vol 465 ◽  
pp. 531-534 ◽  
Author(s):  
Stefano Beretta ◽  
Mauro Filippini ◽  
Luca Patriarca ◽  
Giuseppe Pasquero ◽  
Silvia Sabbadini
Keyword(s):  
Titanium Aluminide ◽  
Electron Beam Melting ◽  
Room Temperature ◽  
Tial Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Gamma Titanium Aluminide ◽  
Titanium Aluminide Alloy ◽  
Fatigue Characteristics

The fatigue properties of a Ti-48Al-2Cr-2Nb alloy obtained by electron beam melting (EBM) with a patented process has been examined by conducting high cycle fatigue tests performed at different loading ratios both at room temperature and at high temperatures, comparable to those experienced by the components during service. Some tests have been conducted in the superlong life regime well exceeding 10 million cycles, highlighting individual fatigue characteristics of the studied TiAl alloy.

scholarly journals Influence of α-Phase Field Heat Treatment on the Tensile and Primary Creep Resistance of a Powder Metallurgical Processed Ti-45Al-5Nb-0.2B-0.2C Titanium Aluminide Alloy

2017 ◽  
Vol 899 ◽  
pp. 418-423
Author(s):  
Rafael Paiotti Marcondes Guimarães ◽  
Juliano Soyama ◽  
Thomas Ebel ◽  
Márcio C. Fredel ◽  
Florian Pyczak
Keyword(s):  
Heat Treatment ◽  
Colony Size ◽  
Titanium Aluminide ◽  
Creep Resistance ◽  
Titanium Aluminides ◽  
Primary Creep ◽  
Heat Treatments ◽  
Titanium Aluminide Alloy ◽  
Metallurgical Processing ◽  
Microstructure Parameters

In powder metallurgical processing the sintering process, as well as heat treatments, can drastically influence microstructure formation. In the case of γ-titanium aluminides, it is critical to achieve certain microstructure parameters, such as colony size, porosity and grain boundary morphology in order to obtain appropriate mechanical properties. In this study, the effect of a heat treatment implemented after sintering with the objective of varying the colony size was investigated. Specimens of Ti-45Al-5Nb-0.2B-0.2C prepared by metal injection moulding and uniaxial pressing of feedstock were used to evaluate the tensile and creep properties. Heat treatments conducted at 1350 and 1400 °C for 3 h led to colony sizes of approximately 100 and 200 μm, respectively. Classically, there is an inverse relationship between grain size and creep resistance, nonetheless, for γ-titanium aluminides, the morphology of the colony boundaries was also found to play a role. The larger colony sizes achieved with the heat treatments did not improve the primary creep resistance, which was explained by the change in the morphology of the colony boundaries as they became larger.

Influence of Heat Treatments on the Microstructure of a Multi-Phase Titanium Aluminide Alloy

2012 ◽  
Vol 49 (3) ◽  
pp. 124-137 ◽  
Author(s):  
E. Schwaighofer ◽  
M. Schloffer ◽  
T. Schmoelzer ◽  
S. Mayer ◽  
J. Lindemann ◽  
...  
Keyword(s):  
Titanium Aluminide ◽  
Heat Treatments ◽  
Titanium Aluminide Alloy ◽  
Multi Phase

AMPCO 940 and AMPCO-TRODE 940

Alloy Digest ◽  
1993 ◽  
Vol 42 (3) ◽  
Keyword(s):  
Copper Alloys ◽  
Heat Treating ◽  
Resistance Welding ◽  
Chromium Alloy ◽  
Heat Treated ◽  
Association Class ◽  
Potential Applications ◽  
Minimum Requirements ◽  
Nickel Silicon ◽  
Plastic Injection

Abstract AMPCO 940 is a precipitation-hardening copper-nickel-silicon-chromium alloy developed for resistance welding and other applications now using the 1% beryllium-copper alloys. The heat-treated alloy is capable of meeting the RWMA (Resistance Welder Manufacturers Association) Class 3 minimum requirements-95,000 psi tensile strength, 90 Rockwell B hardness and 45% IACS electrical conductivity. Potential applications include resistance welding tips, wheels and fixtures. A major use is in plastic injection molding. AMPCO-TRODE 940 is used for repair welding and overlays. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: CU-434. Producer or source: Ampco Metal Inc. Originally published as Ampcoloy 940, April 1982, revised March 1993.

UNS A03560

Alloy Digest ◽  
1986 ◽  
Vol 35 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Good Resistance ◽  
Aluminum Casting Alloy ◽  
Temperature Performance ◽  
Heat Treated

Abstract UNS No. A03560 is a heat-treatable aluminum casting alloy. Normally it is used only when heat-treated (aged) strengths are required. It is recommended for high-strength, pressure-tight castings, intricate shapes and where good resistance to corrosion is needed. Its many applications include crank cases, gear cases, oil pans, airframe fittings and instrument housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-274. Producer or source: Various aluminum companies.

SCHMELZMETALL HOVADUR CCZ

Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Spot Welding ◽  
Zirconium Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Softening Temperature ◽  
Aged Condition ◽  
Heat Treated ◽  
High Softening Temperature ◽  
Made In

Abstract Schmelzmetall Hovadur CCZ is a heat-treatable, copper-chromium-zirconium alloy. In the solution heat-treated and artificially aged condition, this alloy exhibits high thermal and electrical conductivity along with high strength and a high softening temperature. Hovadur CCZ evolved from CuCr1 (CW105C), a precipitation-hardenable alloy first made in the 1930s for spot welding electrodes, for which strength and hardness at temperatures up to 500 °C (930 °F), as well as good electrical and thermal conductivity, are essential. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: Cu-912. Producer or source: Schmelzmetall AG.

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