Some New Fractographic Features in the Fatigue of High-Strength Aerospace Alloys

2008 ◽  
pp. 252-252-15
Author(s):  
B Cina ◽  
I Eldror ◽  
T Kaatz
Keyword(s):  
High Strength ◽  
Aerospace Alloys ◽  
Fractographic Features

Direct-Chill Casting of AA7449 Aerospace Alloy under Electromagnetic and Ultrasonic Combined Fields

2015 ◽  
Vol 828-829 ◽  
pp. 48-52 ◽  
Author(s):  
Reza Haghayeghi ◽  
Plato Kapranos
Keyword(s):  
Chemical Composition ◽  
Electromagnetic Fields ◽  
High Strength ◽  
Direct Chill ◽  
Ultrasonic Vibrations ◽  
Optimum Conditions ◽  
Ultrasonic Fields ◽  
Aerospace Alloys ◽  
Refined Microstructure ◽  
Electro Magnetic

This work is based on investigation of the influence of electromagnetic fields and ultrasonic vibrations and their combination on the resulting microstructure of an AA7449 aerospace aluminium alloy. The results demonstrate the application of the compound electro-magnetic and ultrasonic fields under optimum conditions delivers not only a refined microstructure but also consistent distribution of chemical composition. It suggests an alternative method for producing high strength aerospace alloys which could not be refined through conventional addition of chemical grain refiners.

State of the Art Stainless Steel Provides Improved Properties for Widely Varying Applications

2011 ◽  
Vol 413 ◽  
pp. 341-346 ◽  
Author(s):  
Quan Ming Song ◽  
David Wert
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
High Performance ◽  
Precipitation Hardening ◽  
State Of The Art ◽  
High Strength ◽  
Design Engineers ◽  
Aerospace Alloys ◽  
Industrial Energy

Carpenter Technology Corporation’s Custom 465® stainless steel is a state-of-the-art alloy which has seen its applications expanding at a rapid rate. This alloy is a premium double vacuum melted (VIM/VAR) martensitic precipitation hardening stainless steel that offers an excellent combination of strength, toughness, and corrosion resistance. With its exceptional properties, design engineers have specified the alloy for high-performance components in various industries, such as aerospace, industrial, energy, consumer and medical. The high strength, greater than 250 ksi (1722 MPa) typical, and toughness of the alloy have allowed Custom 465 stainless to be used as a high-strength upgrade to conventional PH stainless steels such as 13-8 and 17-4. The addition of corrosion resistance to the high strength and toughness properties has allowed the alloy to be used as a stainless alternative to non-stainless steels such as AISI 4340 and 300M. This paper will compare mechanical and corrosion resistance properties of Custom 465 stainless steel to those of other PH stainless steels such as 17-4, 15-5, and 13-8, as well as to those of other aerospace alloys such as 300M and AerMet® 100 alloy. In addition, examples of the varied uses of the alloy will be provided, these examples will highlight the benefits obtained by the use of Custom 465 stainless steel over the previous alloys of choice for the applications.

scholarly journals Assessment of the Advantages of Static Shoulder FSW for Joining Aluminium Aerospace Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 1770-1775
Author(s):  
Hao Wu ◽  
Ying Chun Chen ◽  
David Strong ◽  
Philip Prangnell
Keyword(s):  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Systematic Study ◽  
Aluminium Alloys ◽  
High Strength ◽  
Heating Effect ◽  
Friction Stir ◽  
Aerospace Alloys ◽  
Symmetric Temperature

Stationary (or Static) Shoulder Friction Stir Welding (SS-FSW) is a variant of FSW that was developed primarily to improve the weldability of titanium alloys by reducing the through thickness temperature gradient. Surprisingly, SS-FSW has been largely ignored by the Al welding community because it is widely supposed a rotating shoulder is an essential aspect of the process and that the higher conductivity means the surface heating effect of the shoulder is generally beneficial. In the work presented it is shown that SS-FSW has major advantages when welding high strength aluminium alloys; including a reduction in the heat input, a massive improvement in surface quality, and a narrower and more symmetric temperature distribution, which leads to narrower welds with a reduced heat affected zone width and lower distortion. The reasons for these benefits are discussed based on a systematic study aimed at directly comparing both processes.

Manufacturing Titanium and Al-Li Alloy Cryogenic Tanks

2020 ◽  
Vol 837 ◽  
pp. 64-68
Author(s):  
Ho Sung Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo
Keyword(s):  
Laser Beam Welding ◽  
Superplastic Forming ◽  
High Strength ◽  
Manufacturing Processes ◽  
Friction Stir ◽  
Aerospace Applications ◽  
Design Flexibility ◽  
Forming Technology ◽  
Aerospace Alloys ◽  
Cryogenic Tanks

This study presents manufacturing cryogenic tanks for aerospace applications. Since most high strength aerospace alloys like titanium alloys and Al-Li alloys exhibit low formability due to low ductility and work hardening, superplastic forming technology is applied to manufacture hemispherical shapes. Superplasticity is the ability of materials to deform plastically to show very large amount of strains. Advantages of superplastic forming technology include its design flexibility, low tooling cost and short leading time to produce. In this study, various manufacturing processes, like superplastic forming, diffusion bonding, laser beam welding and friction stir welding, are applied to manufacture titanium and aluminum cryogenic tanks. Using these technologies in manufacturing process makes the aerospace components lighter and stiffer, with efficient energy and cost saving.

Decomposition of the metastable beta titanium alloy Ti-15-3

1983 ◽  
Vol 41 ◽  
pp. 264-265
Author(s):  
Y. L. Chen ◽  
S. Fujlshiro
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Alpha Phase ◽  
Thick Sheet ◽  
Omega Phase ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Matrix ◽  
Metastable Beta ◽  
Very High

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

The Nature of Delta Phase Precipitation in Inconel 718

1982 ◽  
Vol 40 ◽  
pp. 724-725
Author(s):  
L. S. Lin ◽  
C. C. Law
Keyword(s):  
Inconel 718 ◽  
Base Alloy ◽  
High Strength ◽  
Physical Metallurgy ◽  
Nickel Base Alloy ◽  
Phase Precipitation ◽  
Weight Percentage ◽  
Delta Phase ◽  
The Subject ◽  
Nickel Base

Inconel 718, a precipitation hardenable nickel-base alloy, is a versatile high strength, weldable wrought alloy that is used in the gas turbine industry for components operated at temperatures up to about 1300°F. The nominal chemical composition is 0.6A1-0.9Ti-19.OCr-18.0Fe-3Mo-5.2(Cb + Ta)- 0.1C with the balance Ni (in weight percentage). The physical metallurgy of IN 718 has been the subject of a number of investigations and it is now established that hardening is due, primarily, to the formation of metastable, disc-shaped γ" an ordered body-centered tetragonal structure (DO2 2 type superlattice).

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

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