1. Light alloys in defence – improving performance in severe environments Dr Cheryll Pitt CEng FIMMM Metallics' Lead, Structural Materials Investigation 1710 Naval Air Squadron 12 December 2013 UNCLASSIFIED © Crown copyright 2013 Dstl 12 October 2015 Dr Matt Lunt CEng FIMMM Principal Scientist - Metallics Dstl

2. 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 12 October 2015

3. 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 12 October 2015 Typhoon foreplane Titanium 6/4 SPFDB X-Core structure Image © BAE Systems Image © Crown

4. 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 12 October 2015 Images © Crown

5. Length of service Equipment usually has life extension programmes –e.g. Scorpion family CVR(T) UNCLASSIFED © Crown copyright 2013 Dstl 12 October 2015 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 Image © Crown

6. 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 12 October 2015 Image © Crown

7. 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 12 October 2015 Image © Crown

8. 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 12 October 2015 Images © Rolls-Royce plc.

9. 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 12 October 2015

10. 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 12 October 2015

11. © Crown copyright 2013 Dstl 12 October 2015 Thank you