Transcript Light Metals and the Defence Industry (Cheryll Pitt, DSTL)

Light alloys in defence – improving
performance in severe environments
Dr Cheryll Pitt CEng FIMMM
Metallics' Lead, Structural
Materials Investigation
1710 Naval Air Squadron
Dr Matt Lunt CEng FIMMM
Principal Scientist - Metallics
Dstl
12 December 2013
08 April 2016
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UNCLASSIFIED
Overview
• Introduction
– The military environment
• Cost, performance, supportability, safety
• Extreme – loads, fatigue cycles, temperatures, strain rates
• Length of service cf. design life
• Repair and overhaul
• A very difficult balance…
• Aluminium, titanium, magnesium
• Conclusions
08 April 2016
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UNCLASSIFIED
Light alloys in the military environment
•
Performance
– Light alloys for weight AND volume reduction
– Specific strength and stiffness
– Ballistics
– Temperature capability
•
Cost
– Cost reduction, e.g. Ti
– R&D cost reduction and acceleration - modelling
•
Image © Crown
Supportability
– Very long lives
– Environmental damage
• Coatings
•
Repair
Typhoon foreplane
Titanium 6/4 SPFDB X-Core structure
– In the field and back at base
Image © BAE Systems
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Some severe environments
• Temperature – polar to tropical
• Extreme loads
• Fatigue cycles – high rates of fatigue
cycle build up (order of magnitude
greater than civil)
• Strain rates – blast, ballistics,
explosively formed projectiles
• Cannot choose not to operate…
– e.g. sand, volcanic ash, ice, CBRN attack
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Images © Crown
Length of service
•
Equipment usually has life extension programmes
– e.g. Scorpion family CVR(T)
• Life extension of 22 years
• 7017 aluminium alloy armour hull
• Re-hulling programme
• Results long service lives
• Implications for insertion of technology
• Repair is an essential consideration
for managing equipment through life
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Image © Crown
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Repair and overhaul
• Methods for repair of light alloy structures essential
• R&D objectives
– Environmental damage and wear (corrosion, fatigue cracks,
erosion, foreign object damage)
• e.g. laser additive repair
• e.g. cold spray technology
– Battle damage (blast, ballistics)
• e.g. friction stir welding of
blast-protective structures
–
NDE methods for detection
Image © Crown
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Aluminium
• Underpinning
– New high performance alloys
•
Without commitment or prejudice
• Air
– REPAIR
Image © Crown
– Performance of structures against ballistics (helicopter lift frame –
8090)
• Land
– New alloys for blast protection
– High performance joining for repair and blast resistance
• Maritime
– Marine aluminium for fast craft and ship superstructure
• Very long term performance, e.g. sensitization in hot climates
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Titanium
• Cost reduction for broader application (e.g.
armour)
– Electro-deoxidation
• New alloys for energy absorption
– Metastable  alloys
• Repair techniques for critical components aeroengine rotors
• Ti-MMCs for mass and volume efficient
aeroengines
• Titanium cellular structures (air and naval)
Images © Rolls-Royce plc.
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Magnesium
• Corrosion protection
• Repair techniques, e.g. cold spray
• Fundamentals of performance in dynamic environments
– Ballistic events
– Challenge to understand deformation of hexagonal metal at
high strain rates
– Multi-scale materials modelling
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Conclusions
• MOD provides technical support to equipment
– Long lives
– Severe and extreme environments
– Unique set of challenges
• MOD invests in R&D in light alloys
– Higher performance
– Better supportability
– Lower cost
• All done in partnership
– Academia, industry, other parts of Government, allies…
08 April 2016
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Thank you
08 April 2016
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