Diffusion Bonding Performance Test Results for New Titanium Alloys (BAOTI and VSMPO Fine Grain Titanium 6Al-4V, TIMETAL 54M and ATI 425) Using Different Temperatures Daniel SANDERS 1 , Larry HEFTI 1 , Al BRYANT 2 , Shanying ZENG 2 , Heping GUO 3 , Pengtao GAI 3 , Zhiqiang LI 3 1 BOEING Company – P.O. Box 3707 MS5K63 – SEATTLE, WA, USA [email protected]2 BOEING Research & Technology China – BEIJING, PR CHINA 3 BAMTRI – Beijing Aeronautical Manufacturing Technology Research Institute – BEIJING, PR CHINA Abstract A joint development program was performed by Boeing and Beijing Aeronautical Manufacturing and Technology Institute (BAMTRI) for testing the diffusion bonding (DB) performance of fine grain titanium alloy 6Al-4V produced by Verknaya Salda Metallurgical Production Association (VSMPO) and Baoji Titanium Industry Co., Ltd. (BAOTI), and also Titanium Metals Corporation (TIMET) alloy TIMETAL 54M and Allegheny Technologies Incorporated (ATI) alloy ATI 425. These materials have all been identified by their manufacturers as exhibiting superplastic performance at a lower temperature range, 775 to 815°C, than conventional titanium 6Al-4V, which is typically superplastic formed at 875 to 925°C. The objective of this study is to determine if the different alloys could be diffusion bonded together with themselves and to each other at different temperatures. This report covers the first phase of the test program, which is to test the DB capabilities of the alloys to themselves. The test includes macroscopic and microscopic evaluations of the resulting bond lines. Keywords : titanium, superplastic forming, SPF, diffusion bonding, DB, 6Al-4V, fine grain, TIMETAL 54M, ATI 425. Introduction Jet engine designers are working towards the introduction of new materials and operational improvements that are creating more fuel efficient thrust for aircraft. One of the most obvious changes is the much larger size of the outer diameter of the high-bypass ratio engines, which is leading aircraft manufacturers to a need for the manufacture of larger engine related components. Not visible to the naked eye, but of much more importance for the engine efficiency, is the higher operating temperatures that the newer engine cores are now operating at. Materials that have traditionally been used for certain engine components, such as fiber reinforced graphite epoxy composite, may no longer be acceptable with the higher service temperature requirement. Superplastic Forming (SPF) and Diffusion Bonding (DB) of titanium may be a practical alternative to other types of high temperature materials for certain parts, as the material size limitation of titanium sheet is no longer a significant factor because of the new capabilities of joining sheets together using friction stir welding (FSW) [1] [2] [3]. It is anticipated that SPF/DB sandwich structure will be used to a greater extent in future aerospace products.
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Diffusion Bonding Performance Test Results for New Titanium Alloys (BAOTI
and VSMPO Fine Grain Titanium 6Al-4V, TIMETAL 54M and ATI 425) Using
Different Temperatures
Daniel SANDERS 1, Larry HEFTI
1, Al BRYANT
2, Shanying ZENG
2, Heping GUO
3,
Pengtao GAI 3, Zhiqiang LI
3
1 BOEING Company – P.O. Box 3707 MS5K63 – SEATTLE, WA, USA
[email protected] 2 BOEING Research & Technology China – BEIJING, PR CHINA
3 BAMTRI – Beijing Aeronautical Manufacturing Technology Research Institute – BEIJING, PR CHINA
Abstract
A joint development program was performed by Boeing and Beijing Aeronautical Manufacturing
and Technology Institute (BAMTRI) for testing the diffusion bonding (DB) performance of fine
grain titanium alloy 6Al-4V produced by Verknaya Salda Metallurgical Production Association
(VSMPO) and Baoji Titanium Industry Co., Ltd. (BAOTI), and also Titanium Metals
Corporation (TIMET) alloy TIMETAL 54M and Allegheny Technologies Incorporated (ATI)
alloy ATI 425. These materials have all been identified by their manufacturers as exhibiting
superplastic performance at a lower temperature range, 775 to 815°C, than conventional titanium
6Al-4V, which is typically superplastic formed at 875 to 925°C. The objective of this study is to
determine if the different alloys could be diffusion bonded together with themselves and to each
other at different temperatures. This report covers the first phase of the test program, which is to
test the DB capabilities of the alloys to themselves. The test includes macroscopic and
microscopic evaluations of the resulting bond lines.
•Testing showed that the material would diffusion bond to itself at 775°C.
•Also diffusion bonds to other alpha-beta alloys at this temperature which is important since standard grain materials typically require around 900°C to fully diffusion bond.
125 µm
Diffusion Bonding of Fine Grain 6Al-4V
Engineering, Operations & Technology | Boeing Research & Technology Metallic Materials & Processes
•Representative cross section of the parts shows a smooth outer surface and the superplastically formed stiffeners. Area between the stiffeners is diffusion bonded – no fasteners required.
Fabrication of SPF/DB Details
Engineering, Operations & Technology | Boeing Research & Technology Metallic Materials & Processes