MECHANICAL PROPERTIES OF 2618 ALUMINUM ALLOY

Mechanical property tests were conducted over the temperature range from room temperature to 400 F on three sizes of hand forged 2618 aluminum alloy billet produced by two suppliers. Tension, notched tension, tension thermal stability, compression, shear, bearing, fracture toughness, creep, axial and rotating beam fatigue, and stress corrosion properties were determined. Tension, compression, shear and bearing properties were statistically analyzed to determine values similar to A and B design values found in MIL-HDBK-5. Alloy 2618-T61 retains its static and fatigue properties well at elevated temperatures and has good resistance to creep deformation. At 400 F 2618 retains approximately 80 of its room temperature properties after short time exposure. Applied stresses exceeding the yield strength are required for appreciable creep to occur at 250 F, while stresses of approximately 75 and 50 percent of the yield strength at temperature are required for 1 creep to occur in 1000 hours at 325 F and 400 F. Plane strain fracture toughness at all areas in the billet in the longitudinal direction was similar to 7075-T6 however, the quarter- thickness and surface areas for the billet in the long transverse direction generally had lower fracture toughness than most data reported for 7075-T6. Stress corrosion tests indicated that 2618 is susceptible to stress corrosion cracking in the two transverse directions when stressed to 75 of its yeild strenght.