New Titanium Alloys for Aerospace Applications

1
New Titanium Alloysfor Aerospace Applications

• Geoff Hartle, VSMPO Tirus Ltd
• TIG Conference
• The Belfry
• 23rd 24th June 2009

2
New Titanium Alloys

• ALLOY
• Ti 5Al-5Mo-5V-3Cr
• Ti 6Al-4V Fine-Grain
• Ti 3Al-3Mo-3V-1Zr

• APPLICATION
• Airframe Components
• SPF Sheet
• Hydraulic Tubing

3
Ti 5Al-5Mo-5V-3Cr

• Evolved from Russian alloy, VT-22
• Commonly used for airframe structural forgings
• 1995/1996 VSMPO began work with Boeing
• Goal Higher strength / lower cost than
  10V-2Fe-3Al
• Candidate alloy for forged, landing gear
  components
• Potential alloy for investment castings

4
Ti 5Al-5Mo-5V-3Cr

• Advantages Over 10V-2Fe-3Al
• Less prone to segregation
• Higher ßt (50 C)
• Better die fill, longer die-life
• Better harden-ability in thick sections
• Up to 6 section thickness vs. 3 for 10V-2Fe-3Al

5
Ti 5Al-5Mo-5V-3Cr

• Advantages Over 10V-2Fe-3Al
• Air cool vs. water quench less distortion
• Higher strength with equivalent ductility and
  fracture toughness
• Potentially less costly to machine

6
Ti 5Al-5Mo-5V-3Cr
Billet Properties
7
Ti 5Al-5Mo-5V-3Cr
Forging Properties
8
Ti 5Al-5Mo-5V-3Cr

• Status of Development
• Boeing specification developed
• Currently used in several applications on 787 and
  Sukhoi Superjet 100 (die forgings)
• Improved version being studied for A350
  application

9
Ti 6Al-4V Fine-grain (Fg)

• Developed for Super-Plastic Forming (SPF)

10
Ti 6Al-4V Fine-grain (Fg)

• Grain size lt 1 µm vs. 3 µm in standard
• Enables lower forming temperatures
• 760 C vs. 900 C (1400 F vs. 1650 F)
• Eliminates a-case
• Improves die-life
• Reduces press maintenance requirement
• Improves operator safety and comfort

11
Ti 6Al-4V Fine-grain (Fg)

• Mechanical Properties of Delivered Sheet

12
Ti 6Al-4V Fine-grain (Fg)

• Mechanical Properties at SPF Temperatures

13
Ti 6Al-4V Fine-grain (Fg)

• Stress/Strain Testing at SPF Temperatures

Fg, 760?, strain rate 110-3 s-1
Fg, 760?, strain rate 310-4
s-1 Fg, 760?, strain rate 110-4 s-1
3µ, 900?, strain rate 310-4 s-1
14
Ti 6Al-4V Fine-grain (Fg)

• Status of Development
• Boeing specification developed
• Use on several parts on Boeing 787
• Study of other opportunities

15
Ti 3Al-3Mo-3V-1Zr

• High-pressure hydraulic tubing
• Current alloy is Ti 3Al-2.5V (CWSR)
• Unable to swage-form compression fittings
• Leads to costly welding of fittings

16
Ti 3Al-3Mo-3V-1Zr

• Cold-rolled, annealed VST 3331 has 20 more
  plasticity yet equivalent strengths

17
Ti 3Al-3Mo-3V-1Zr

• CWSR VST 3331 shows 15 improvement in strength
  with equivalent ductility and flaring capability
• Offers potential to increase operating pressures

18
Ti 3Al-3Mo-3V-1Zr

• Status of Development
• Initial swage forming trial successful
• Additional sample lot in production for further
  evaluation
• Coil being produced for ducting trial