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The Application Experience of Superplasticity and Creepage Effects for Aircraft Components Production Made of Sheet Metal and Plates. D.E., associate professo Research Supervisor: Kurlaev N.V. Novosibirsk State Technical University Aircraft Faculty Postgraduate student: Zhelobkov V.G. Aircraft Production Department

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The Application Experience of Superplasticity and Creepage Effects for Aircraft Components Production

Made of Sheet Metal and Plates.

D.E., associate professor

Research Supervisor:

Kurlaev N.V.

Novosibirsk State Technical UniversityAircraft Faculty

Postgraduate student:Zhelobkov V.G.

Aircraft Production Department

Contents

1. Aircraft Faculty

2. Titanium and its properties;

3. Superplasticity. Effects and mechanisms;

4. Technological processes with superplasticity application;

5. Improving of forming process for titanium panels

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Aircraft faculty

• Founded in 1957

• Divided from Mechanical Faculty in 1959

• Faculty consists of 7 Deparments:1) Aircraft production Department;

2) Aero- Hydrodynamics Department;

3) Autonomous information and control systems Departments;

4) Engineering ecological problems Department

5) Aircraft durability Department

6) Engine Department

7) Engineering thermal physics Department.3

Titanium in aircraft production

•1 Aircraft skins;•2 Engine parts;•3 Tubes in hydro- and fuel systems; •4 Longerons;•5 Rivets;•6 Wing ribs;•7 Armor

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Mechanical and physical properties of Titanium and its alloys

Disadvantages

• Small period of industrial development;

• Low plasticity;• Low formability in cold conditions;• Brittle Fracture

Advantages

• Low density;

• High ductility;• High hardness;• High strength;• Long time to serve;• Resistant to water, acid & alkali

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Superplasticity as a property of metal materials

Superplasticity is the ability of polycrystalline metal materials to deform intensively with low inner stresses under certain temperatures and deform rates.

Sample with 1950% of elongation

Main characteristics of superplastic deformation:

• 1) plasticity sources increasing;

• 2) Stress decreasing in deformation process;• 3) Hardening absence during plastic flow ;• 4) Relation between stresses and rates of plastic

flowing

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Three mechanisms to provide superplasticity

1. Grain-boundary sliding

2. Intragranular dislocation sliding

3. Diffusion creepage

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Technological processes with superplasticity application

•Drop hammer forming;•Press brake forming Diffusion bonding;•Hot forming;•Stretch forming

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Superplastic forming of Titanium panels in Novosibirsk Aircraft production Enterprise.

- high temperature oven. - heat-isolated camera - 40 pairs of opposite pushers made of heat-resistant steel- spiral heaters made of nickel-chromium alloy.

- panel is suspended by two chains

- numeric program direction - simultaneous motion of pushes- special reference trajectory and speed

In fact the formation unit is a needle stamp with program control.

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Appeared problems with forming equipment

Hollows on panels after forming with pushers

Required accuracy was not achieved

Ununiform heating of titanium panel

Objectives

1) Defining the base for panel in the camera;

2) High reliability of all elements in the forming system;

3) Heating uniformity in the range of ±5°;

4) Favorable forming conditions;

5) New forming system development for sheet-metal aircraft parts

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Future plans

• Finite-element analysis of forming process

• Stiffness calculations of forming system apparatus

• Optimal temperature and forming rate estimation for different materials and alloys

• Determination of relation between number of forming setups and mechanical properties

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References

• 1. Appel F., Paul J.D.H., Oehring M. Gamma Titanium Aluminide Alloys: Science and Technology. Wiley-VCH Verlag Gmbh & Co KGaA,2008.

• 2. Бернштейн М.Л. Структура деформирования металлов. - М.: Металлургия, 1977.

• 3. Полухин П.И., Горелик С.С., Воронцов В.К. Физические основы пластической деформации. - М.: Металлургия, 1982

• 4. Чумаченко Е.Н., Смирнов О.М., Цепин М.А. Сверхпластичность: материалы, теория, технологии. Серия «Синергетика: от прошлого к будущему». - М.: Комкнига, 2005.

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Thank you for your attention

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