ALUMINUM-LITHIUM ALLOY 2099-T86 Low Density, High Strength Plate DESCRIPTION APPLICATIONS Alcoa developed third-generation aluminum-lithium alloy AA 2099 to have low density, high strength, high modulus, moderate fracture toughness, and excellent fatigue crack growth and corrosion resistance. The composition and thermal mechanical processes for 2099 were especially designed to overcome the deficiencies in earlier Al-Li alloys such as poor corrosion resistance and high anisotropy. Compared to alloys 7075 and 7050, alloy 2099 offers similar strength and improved fatigue crack growth and corrosion resistance with 6 to 7% lower density. Alloy 2099 plate can replace alloys 7075, 7050, and other high strength plate alloys in applications requiring high strength and moderate fracture toughness. The fabrication characteristics of 2099 plate are significantly improved over second-generation Al-Li alloys such as AA 2090 and AA 8090. Customers have successfully fabricated both aircraft and spacecraft components from 2099 plate. COMMERCIAL STATUS Alcoa 2099-T86 plate has been supplied commercially to a customer specification since 2007 and is currently used for internal aircraft structure. 2099-T86 plate is also covered by industry specification AMS 4458 and material design allowables are available in the MMPDS Handbook. Alloy 2099 plate is available in the high strength T86 temper. The available thickness range is 0.5 to 2.0 inches (12.7 to 50.8 mm). CHEMICAL COMPOSITION Chemical Composition Limits • AA 2099 (Wt.%)* Cu Li Zn Mg Mn Zr Ti Fe Si Al 2.4 – 3.0 1.6 – 2.0 0.40 – 1.0 0.10 – 0.50 0.10 – 0.50 0.05 – 0.12 0.10 max 0.07 max 0.05 max Remainder *Other elements: 0.05 wt.% max (each); 0.15 wt.% max (total) Static Properties • Al-Li 2099-T86 Plate • Minimum Values (S-Basis) Alloy/Temper Direction Thickness, Inch (mm) 2099-T86 (AMS 4458) 7075-T7351 (AMS 4078) 7050-T7451 (AMS 4050) 0.500 – 2.000 (12.70 – 25.40) 1.001 – 2.000 (25.42 – 50.80) 0.250 – 2.000 (6.350 – 50.80) L 71 (490) 69 (476) 74 (510) LT 72 (496) 69 (476) 74 (510) L 63 (434) 57 (393) 64 (441) LT 62 (427) 57 (393) 64 (441) L 6 na 10 LT 5 6 9 Tension Modulus, Msi (GPa) 11.3 (77.9) 10.3 (71.0) 10.3 (71.0) Compression Modulus, Msi (GPa) 11.5 (79.3) 10.6 (73.0) 10.6 (73.0) Density, lb/in , (g/cm ) 0.095 (2.63) 0.101 (2.81) 0.102 (2.83) Tensile Strength, Ftu, ksi (MPa) Tensile Yield, Fty, ksi (MPa) Elongation, %, 4D 3 3 CONTACT AND PROCUREMENT For additional information on 2099-T86 plate, contact your local Alcoa Sales Account Manager. FATIGUE AND DAMAGE TOLERANCE PROPERTIES The fracture toughness and S-N fatigue resistance of 2099-T86 is similar to that of 7050-T7451, and better than that of 7075T7351. The fatigue crack growth resistance of 2099-T86 is superior to that of both 7050-T7451 and 7x75-T7351 alloys. Fracture Toughness • 2099-T86 Alloy/Temper Orientation KIc Minimum ksi√in (MPa√m) KIc* Typical ksi√in (MPa√m) L-T 30 (33) 40 (44) T-L 25 (27) 33 (36) L-T na 30 (33)* T-L na 27 (30)* L-T 29 (32) 40 (44)* T-L 25 (27) 33 (36)* 2099-T86 (1.00 – 2.00 in.) 7075-T7351 (> 1.00 in.) 7050-T7451 (1.00 – 2.00 in.) * Source: MMPDS Handbook S-N Fatigue FCG Curves 1.0E-02 2099-T86 7050-T7451 40 T-L Orientataon R=0.1, Humid Air, Frequency=25 Hz 1.0E-03 30 20 10 da/dN (in/cycle) Maximum Net Stress (ksi) 50 Longitudinal Kt(net)=2.5 (Double Hole) R=0.1, Lab Air Frequency: 25-30 Hz 0 1.0E+04 1.0E+05 1.0E+06 1.0E-04 1.0E-05 1.0E-06 1.0E+07 Cycles to Failure 2099-T86 1.0E-07 7050-T7451 7475-T7351 1.0E-08 1 10 100 K (ksi in) CORROSION RESISTANCE The corrosion resistance of 2099-T86 plate is exceptional. The exfoliation rating of 2099-T86 is typically P (pitting only, ASTM G34 rating) in the accelerated Dry Bottom MASTMAASIS tests (ASTM G 85 Annex 2) and after many years of seacoast exposure. The guaranteed SCC resistance of 2099-T86 (ASTM G47) is 50 ksi (345 MPa) in the ST direction; the highest of any commercial aerospace plate product. SCC Resistance • 2099-T86 Alloy/Temper Direction SCC Minimum ksi (MPa) 2099-T86 (0.75 – 2.00 in.) LT 55 (370) ST 50 (345) 7050-T7451 (> 1.00 in.) ST 35 (241) 7075-T7351 (1.00 – 2.00 in.) ST 43 (295) ALCOA AEROSPACE AND AUTOMOTIVE PRODUCTS P.O. BOX 8025 • BETTENDORF, IOWA 52722 • 1-800-523-9596 • www.alcoa.com Product specifications are subject to change without notice. ©2016 Alcoa Inc. 1/16