Weldalite (trademark) 049 (Al 2095-T8): Anisotropy Effects at CryogenicConditions

摘要

Tensile, fracture, and FCGR testing was performed on a plate of the aluminum-lithium alloy Weldalite(TM) 049 (Al 2095-T8) over a temperature range from ambient to liquid helium (4K) conditions. Properties were developed on specimens removed from various orientations within a 12.7 mm (1/2 in) nominal thick plate to characterize anisotropy with respect to strength and toughness. Strength and FCGR properties are compared to the conventional aluminum alloy 2219-T87, developed for similar cryogenic applications. Results indicate a high degree of anisotropy with respect to strength and ductility, with the lowest strength/highest ductility occurring at 45-60 deg from the rolling direction. Decreases in test temperature led to higher strengths and similar anisotropic behavior, with little or no change in ductility. Fracture toughness measurements did not reveal any significant orientation effects, with toughness levels insensitive to the cryogenic temperatures examined. It was not possible to develop valid FCGR data on C(T) samples oriented in either the T-L or T-L plate directions due to out-of-plane cracking. Constant amplitude FCGR data generated on 45 deg oriented samples are comparable with reference data on similar Weldalite material for the T-L and L-T directions, though a slight degree of anisotropy appears to exist at lower values of Delta K. FCGR data obtained at liquid nitrogen and liquid helium test conditions were identical and only slightly lower than similar data developed under ambient conditions. Weldalite(TM) 049, Fracture toughness, Cryogenic, Aluminum-lithium, Tensile, 2219, 2095, Fatigue crack growth.