ALLOY 2099-T83 AND 2099-T8E67 EXTRUSIONS High Strength / Low Density Extrusions ALCOA AEROSPACE TECHNICAL FACT SHEET D E S C R I P T I O N Alcoa has developed Al-Li Alloy 2099, also designated C460, for use in aerospace and high strength applications requiring low density, high stiffness, superior damage tolerance, excellent corrosion resistance and weldability. Li additions increase the strength and modulus of Al alloys while lowering their density. Alloy 2099 extrusions are available in two tempers from 0.050 to 3.00 inch (1.2 to 76 mm) thicknesses. Alloy 2099-T83 has high strength and excellent corrosion resistance with moderate fracture toughness. Alloy 2099-T8E67 has somewhat lower strength, but very high fracture toughness and excellent fatigue crack growth resistance. Alloy 2099 is also available in T3- and T4- type and O tempers that meet stringent requirements of forming applications. A P P L I C A T I O N S Alloy 2099 extrusions can replace 2xxx, 6xxx, and 7xxx aluminum alloys in applications such as statically and dynamically loaded fuselage structures, lower wing stringers, and stiffness dominated designs. Alloy 2099 extrusions have exhibited very good machining, forming, fastening, and surface finishing behavior in production facilities. M E C H A N I C A L P R O P E R T I E S The data in the tables show how the tempers compare in static, damage tolerant, and corrosion properties. The T83 temper can meet or exceed the strength of 7075-T6511 and 7050-T76511 extrusions with improved corrosion and stiffness, and lower density. The T8E67 temper has strength much higher than 2024-T3511 or 2026-T3511 with better toughness, much better corrosion resistance and lower density. CHEMICAL COMPOSITION LIMITS (WT.%) Cu 2.4 - 3.0 Li 1.6 - 2.0 Zn 0.4 - 1.0 Mg 0.10 - 0.50 Mn 0.10 - 0.50 Zr 0.05 - 0.12 Ti 0.10 max Fe 0.07 max Si 0.05 max Be 0.0001 max Others, Each 0.05 max Others, Total 0.15 max Al Remainder MECHANICAL PROPERTIES 2099-T83/T8E67 Typical Values Alloy/Temper Thickness 2099-T83 2099-T8E67 0.50–0.999" 1.00–2.5" 1.00–2.5" Tensile Strength, ksi (Mpa) L LT 81 (560) 76 (525) 83 (595) 75 (520) 77 (530) 74 (510) Yield Strength, ksi (Mpa) L LT 76 (525) 70 (485) 78 (505) 68 (470) 70 (485) 62 (430) Compressive Yield Strength, ksi (Mpa) L LT 75 (520) 75 (520) 78 (540) 70 (485) 69 (475) 64 (440) Elongation, % L 9 9 10 L-T T-L – – 27 (30) 25 (27) 60 (66) 50 (55) P/EA P/EA P/EA – 48 (330) 36 (250) Toughness KIC ksi√in (Mpa√m) EXCO Rating SCC (LT direction) Min ksi (Mpa) in ASTM G47 Tension Modulus, Msi (Gpa) Density, lbs./in (g/cm ) 3 3 11.3 (78) 0.095 (2.63) PRODUCT SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE AEAP-ALCOA ENGINEERED AEROSPACE PRODUCTS 3131 MAIN STREET • LAFAYETTE, INDIANA 47905 • (765) 771-3521 • www.alcoa.com/AEP Revised 08/05 T O U G H N E S S A N D F A T I G U E The fatigue crack growth resistance and the S/N fatigue performance of Alloy 2099 also shows improvement versus 2024-T3511 which has been a standard product for applications considered fatigue critical. FCG CURVES TOUGHNESS VS. STRENGTH 2099-T8E67 2099-T83 7050-T76511 2026-T3511 70.0 60.0 1.0E-02 1.0E-03 da/dN (inch/cycle) L -T Fracture T ou gh ness (ksi√in) 80.0 (da/dN vs ∆K , C(T) L-T, RH > 90% , R = 0.1 , Freq = 25 Hz) 50.0 40.0 30.0 1.0E-04 2099-T8E67 2099-T83 2026-T3511 2224-T3511 1.0E-05 1.0E-06 1.0E-07 1.0E-08 20.0 50.0 60.0 70.0 80.0 1.0E-09 1.00 Longitudinal Yield Strength (ksi) 10.00 delta∆K K (ksi√in) (ksi in^ ) 100.00 S/N FATIGUE CURVES 70.0 60.0 20 99 -T 8 E 67 2 02 6-T 35 11 20 99 -T 8 3 2 02 4-T 35 11 Ma ximum Stre ss, k si 50.0 40.0 30.0 20.0 K t= 2.3 R = + 0 .1 F req = 30 H z H u m id ity > 90 % L o n g itu d in al D ire c tio n 10.0 d id n o t fa il 0.0 1.0E + 03 1.0E + 04 1.0E + 05 1 .0E + 06 1.0E + 07 1.0E + 08 C yc le s , N C O R R O S I O N The corrosion resistance of Alloy 2099 is much better than 7075-T6511 and 2024-T3511 with both the T8E67 and T83 tempers receiving EA (mild exfoliation) or better exfoliation ratings compared to the conventional alloys ED (very severe exfoliation) ratings. The stress-corrosion cracking performance is also much improved with long transverse ratings (per ASTM G64) of “A” for both tempers of Alloy 2099 compared to “B” and/or “C” for conventional alloys. C O N T A C T A N D P R O C U R E M E N T For additional information on 2099-T83 or -T8E67 extrusions, contact your local Alcoa Aerospace Sales Account Manager. PRODUCT SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE AEAP-ALCOA ENGINEERED AEROSPACE PRODUCTS 3131 MAIN STREET • LAFAYETTE, INDIANA 47905 • (765) 771-3521 • www.alcoa.com/AEP Revised 08/05