Mechanical properties of aluminium-copper-lithium alloy AA2195 at cryogenic temperatures

Abstract

Tensile testing was performed on a 4. mm thick sheet of the aluminum-lithium alloy AA2195 in T87 (solution treatment. +. water quenching. +. 7% cold work. +. peak aging) temper which was subjected to 7% cold working by combination of cold rolling and stretching, over a temperature range from ambient to liquid hydrogen (20. K) conditions. Properties were evaluated in longitudinal as well as transverse directions to characterize anisotropy with respect to strength and ductility. Strength and ductility were compared to the conventional aluminum alloy AA2219-T87, developed for similar cryogenic applications. Decreases in test temperature led to higher strengths with little or no change in ductility. As the temperature decreases, the differences between ultimate tensile strength as well as yield strength for two different combinations of cold roll and stretch studied in the present work, narrows down and become equal at 20. K. © 2014 Elsevier Ltd.