Superplastic Blow Forming of Aerospace Components

2014 ◽  
Vol 622-623 ◽  
pp. 819-822
Author(s):  
Ho Sung Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo

Many metals, such as titanium and superalloys, are used for a wide range of aerospace applications, which include aircraft gas turbine engine and space launcher propulsion engine. In order to manufacture a stiffened extension with superplastic blow forming at elevated temperature, the structural integrity of the joint part was investigated since the welded or bonded joint of internal channels should maintain its strength during superplastic blow forming process. Various types of joint methods were performed in order to investigate microstructural and mechanical properties of the bonded specimen at elevated temperature. In this paper, the possibility of manufacturing combustion chamber and other aerospace components with superplastic blow forming of titanium and superalloy was demonstrated. An innovative manufacturing method to produce complex configuration from titanium multi-sheets by superplastic forming with low hydrostatic pressure was presented. The result also shows that the manufacturing method with superplastic blow forming of multi-sheets of IN718 alloy has been successfully demonstrated for near net shape forming of subscale nozzle extension cone with internal channels.

Author(s):  
G.E. Kim ◽  
P.G. Tsantrizos ◽  
S. Grenier ◽  
A. Cavasin ◽  
T. Brzezinski

Abstract PyroGenesis Inc. has developed a unique Vacuum Plasma Spraying (VPS) near-net-shape forming process for the production of multilayered free-standing components. Initial evaluation on the feasibility of applying this process for the production of gas turbine engine components has been performed. The VPS near-net-shape forming process consists of: selecting an appropriate mold material; preconditioning of mold surface ; depositing metallic, ceramic, or composite layers ; and removing mold from the spray-formed structure. The near-net-shape components are heat treated to improve their mechanical properties. A suitable heat treatment cycle was developed for the VPS-applied superalloy. Much of the recent improvements in gas turbine engine performance has been attributed to the introduction of thermal barrier coatings (TBC) for superalloy components. There exist, however, some limitations in current fabrication methods for closed hot-section components: less than ideal coating quality; welding; limited choice of superalloy material; etc... PyroGenesis has used VPS near-net-shape forming to fabricate closed components with an yttria-stabilized-zirconia inner layer, CoNiCrA1Y bond coat, and IN-738LC outer layer. The results from the initial study demonstrate the feasibility of producing near-net-shape components with good coating structures, superior superalloy materials, and the absence welds. The mold was reusable after minor surface conditioning. The TBC showed uniform thickness and microstructure with a smooth surface finish. The bond coat and structural superalloy layers were very dense with no signs of oxidation at the interface. After heat treatment, the mechanical properties of the IN-738LC compare favourably to cast materials.


Author(s):  
S. George Luckey ◽  
Peter A. Friedman

A novel sheet metal forming technology based on aspects of both warm forming and superplastic forming has recently been developed. The new forming process, referred to as hot draw mechanical preforming (HDMP), uses two sequential steps to form a panel within a single tool at elevated temperature. In the first step, the cushion system acts on a binder and upper die to draw the blank over a punch which serves to draw in metal from the perimeter of the blank. In the second step gas pressure is applied to finish the panel details. This two step process of drawing in metal followed by gas forming can result in a significant expansion of the forming envelope for conventional AA5xxx series aluminum sheet alloys commonly used within the automotive industry. Similar to SPF, the HDMP process is performed within a single forming press equipped with heated platens and using gas pressure to shape the component during elevated temperature forming. However, the HDMP process utilizes a blankholder to control the flow of material into the forming cavity during the drawing stage and therefore requires the addition of an integrated cushion system in the bed of the press. HDMP dies are of interest in automotive applications because they maintain the low-investment attributes of SPF tooling while also significantly reducing the forming time as compared to conventional SPF. This work details the CAE based design of an HDMP die to form a one-piece aluminum door inner that can not be formed with conventionally forming processes. Critical aspects addressed in the development of the die include manufacturing targets, part design for manufacturing, and die design for operation at elevated temperature.


Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1191
Author(s):  
Hani Hilal ◽  
Robert Lancaster ◽  
Dave Stapleton ◽  
Gavin Baxter

Additive manufacturing (AM) is a novel near net shape manufacturing technology that joins metallic powders layer upon layer in conjunction with 3D model data and as such offers tremendous potential to a wide range of industrial sectors given its ability to produce highly intricate components with very little material wastage. Subsequently, the aerospace industry has become particularly interested in utilising AM as a means of manufacturing nickel-based superalloys for high-temperature applications, such as non-rotating components within gas turbine engines, which are traditionally fabricated through traditional cast and wrought methodologies. As a result of this, a detailed understanding of the influence of key process variables on the structural integrity of the different experimental builds is required. A semi-empirical quantitative approach for melt track analysis has been conducted and the impact on melt track sizing and defect forming mechanisms in the as-built and heat-treated condition is investigated.


2012 ◽  
Vol 735 ◽  
pp. 338-346 ◽  
Author(s):  
Larry D. Hefti

Titanium is difficult to fabricate into complex aircraft configurations. There is several elevated temperature forming techniques that are available to produce titanium components for aircraft, two of which will be discussed here: Superplastic Forming (SPF) and hot forming. SPF is used when complex shapes are required, for example, tight radii, and uses a tool that contains the required configuration and seals around the periphery so inert gas pressure can be used to form the material. Since SPF is a process where the material is stretched, the part is not a uniform thickness when completed. A variation of the process combines SPF with diffusion bonding (SPF/DB) of two or more pieces of titanium together to produce integrally stiffened structure containing very few fasteners. The hot forming process uses matched metal tools, offset by the thickness of the starting material, are used to form the part contour at elevated temperature. The required part geometry usually contains no sharp features that have to be formed. Since the material is free to move as the die is closed, the part is fairly uniform in thickness when completed.


MRS Bulletin ◽  
1993 ◽  
Vol 18 (7) ◽  
pp. 35-41 ◽  
Author(s):  
John J. Petrovic

Structural materials that can withstand oxidizing and aggressive environments at temperatures above 1000°C constitute an enabling materials technology for a wide range of applications in the industrial, aerospace, and automotive arenas. A few of the industrial uses for such materials are furnace elements and components, power generation components, high-temperature heat exchangers, gas burners and igniters, and high-temperature filters. Aerospace applications include turbine aircraft engine hot-section components such as blades, vanes, combustors, nozzles, and seals. Automotive applications involve components such as turbocharger rotors, valves, glow plugs, and advanced turbine engine parts.There is increasing interest in silicide-based compounds for high-temperature structural uses under oxidizing conditions in the range of 1200–1600°C. In this temperature range, for oxidation and strength reasons, the choice of materials is limited to the silicon-based structural ceramics such as Si3N4 and SiC, and the new class of “high-temperature structural silicides.” An extensive survey of progress in the area of high-temperature structural silicides has recently been published.


Author(s):  
Michal Mis ◽  
Richard Hall ◽  
Julian Spence ◽  
Nwabueze Emekwuru ◽  
Kevin Kibble ◽  
...  

The superplastic forming process is used in a wide range of high-value-added manufacturing sectors to make lightweight, complex-shaped components for high-performance applications. Currently, it is a high-cost process, for example, the superplastic forming of titanium alloys involves a high-temperature furnace, costly (mould) tooling and has a high utilization of resources such as argon gas and energy. The authors of this article propose a prototype for next-generation superplastic forming laboratory equipment. The aim is to develop improved methods, particularly for heat management in the superplastic forming process, to allow a more widespread application of the process to manufacture lower cost products. The next-generation superplastic forming tool comprises a tool in the form of a hemispherical shell, pressure chamber with incorporated water cooling system and an infrared heating system. The construction, usability and suitability of the next-generation superplastic forming equipment have been proven by a series of physical experiments, and numerical simulations are performed and the results are presented and discussed in this article.


Author(s):  
Gerald B. Feldewerth

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.


Alloy Digest ◽  
1978 ◽  
Vol 27 (7) ◽  

Abstract ALMAR 300 Alloy is a vacuum-melted ultra-high-strength steel. The annealed structure of this alloy is essentially a carbon-free, iron-nickel martensite (a relatively soft Rockwell C 28) that can be strengthened by cold working and elevated-temperature (900-950 F) age hardening to useful yield strengths as high as 300,000 psi. The unique properties of this alloy make it suitable for a wide range of section sizes. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-349. Producer or source: Allegheny Ludlum Corporation.


Author(s):  
Dhia Charni ◽  
Svetlana Ortmann-Ishkina ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Jérémy Epp

AbstractThe radial infeed rotary swaging is widely used as a diameter reduction forming process of axisymmetric workpieces, improving the mechanical properties with excellent near net shape forming. In the present study, rotary swaging experiments with different parameter setups were performed on steel tubes and bars under different material states and several resulting property modifications were investigated such as stress-strain curve, hardness, fatigue strength and surface residual stresses. The results show a significant work hardening induced by the rotary swaging process and an improvement in the static and dynamic mechanical properties was observed. Furthermore, the hardness distribution was homogenous in the cross section of the rotary swaged workpieces. Moreover, depending on the process conditions, different residual stresses distribution were generated along the surface.


2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianye Gao ◽  
Tao He ◽  
Yuanming Huo ◽  
Miao Song ◽  
Tingting Yao ◽  
...  

AbstractDuctile fracture of metal often occurs in the plastic forming process of parts. The establishment of ductile fracture criterion can effectively guide the selection of process parameters and avoid ductile fracture of parts during machining. The 3D ductile fracture envelope of AA6063-T6 was developed to predict and prevent its fracture. Smooth round bar tension tests were performed to characterize the flow stress, and a series of experiments were conducted to characterize the ductile fracture firstly, such as notched round bar tension tests, compression tests and torsion tests. These tests cover a wide range of stress triaxiality (ST) and Lode parameter (LP) to calibrate the ductile fracture criterion. Plasticity modeling was performed, and the predicted results were compared with corresponding experimental data to verify the plasticity model after these experiments. Then the relationship between ductile fracture strain and ST with LP was constructed using the modified Mohr–Coulomb (MMC) model and Bai-Wierzbicki (BW) model to develop the 3D ductile fracture envelope. Finally, two ductile damage models were proposed based on the 3D fracture envelope of AA6063. Through the comparison of the two models, it was found that BW model had better fitting effect, and the sum of squares of residual error of BW model was 0.9901. The two models had relatively large errors in predicting the fracture strain of SRB tensile test and torsion test, but both of the predicting error of both two models were within the acceptable range of 15%. In the process of finite element simulation, the evolution process of ductile fracture can be well simulated by the two models. However, BW model can predict the location of fracture more accurately than MMC model.


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