light alloys in defence – improving performance in severe environments dr cheryll pitt ceng fimmm...
TRANSCRIPT
Light alloys in defence – improving
performance in severe environmentsDr Cheryll Pitt CEng FIMMMMetallics' Lead, Structural Materials Investigation1710 Naval Air Squadron
12 December 2013
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Dr Matt Lunt CEng FIMMM
Principal Scientist - Metallics
Dstl
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
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
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
• Supportability
– Very long lives
– Environmental damage
• Coatings
• Repair
– In the field and back at base
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Typhoon foreplaneTitanium 6/4 SPFDB X-Core structure
Image © BAE Systems
Image © Crown
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
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Images © Crown
Length of service
• Equipment usually has life extension programmes
– e.g. Scorpion family CVR(T)
UNCLASSIFED© Crown copyright 2013 Dstl
April 21, 2023
• 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 lifeImage © Crown
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
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Image © Crown
Aluminium• Underpinning
– New high performance alloys• Without commitment or prejudice
• Air
– REPAIR
– 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
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Image © Crown
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)
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
Images © Rolls-Royce plc.
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
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
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…
UNCLASSIFIED© Crown copyright 2013 Dstl
April 21, 2023
© Crown copyright 2013 Dstl
April 21, 2023Thank you