Cryogenic Mechanical Properties of Al-Cu-Li-Zr Alloy 2090

Abstract

The mechanical properties of aluminum-lithium alloy 2090-T8E41 were evaluated at 298 K, 77 K, and 4 K. Previously reported tensile and fracture toughness properties at room tem.,lerature were confirmed. This alloy exhibits substantially improved properties at cryogenic temperatures; the strength, elongation, fracture toughness and fatigue crack growth resistance all improve simultaneously as the testing temperature decreases. This alloy has cryogenic properties superior to those of aluminum alloys currently used for cryogenic applications. This report was done with support from the Department of Energy. Any conclusions or opinions expressed in this report represent solely those of the author(s) and not necessarily those of The Regents of the University of California, the Lawrence Berkeley Laboratory or the Department of Energy. Reference to a company or product name does not imply approval or recommendation of the product by the University of California or the U.S. Department of Energy to the exclusion of others that may be suitable.

Mechanical behavior of aluminum-lithium alloys at cryogenic temperatures

“…However, as illustrated by figure 2, decreasing the temperature did not alter the fracture mode or morphology [1]. More recently, Dorward [2] has suggested that the improvement in the fracture toughness of 2090-TS alloy at low temperature is due to increased short-transverse delamination (splitting in the plane of the plate).…”

“…In addition, previous work has indicated that at low temperatures aluminum-lithium alloys display improved toughness and an improved strength-toughness relationship in the Land LT directions [1][2][3]. The most extensively studied alloy is alloy 2090-TBl, of nominal composition Al-2.7Cu-2.2Li-0.12Zr in weight 2 percent.…”

“…The most extensively studied alloy is alloy 2090-TBl, of nominal composition Al-2.7Cu-2.2Li-0.12Zr in weight 2 percent. The cryogenic mechanical properties of alloy 2090-T81 have been characterized [1,2] and are summarized below.…”

“…To test this observation for the present case,. the fracture surfaces of the specimens described in reference [1] were specifically examined for ·increased cracking perpendicular to the fracture surface; however; no qualitative difference was observed. '…”

“…The most extensively studied alloy is alloy 2090-TBl, of nominal composition Al-2.7Cu-2.2Li-0.12Zr in weight 2 percent. The cryogenic mechanical properties of alloy 2090-T81 have been characterized [1,2] and are summarized below.The most striking feature of the low temperature behavior of alloy 2090-T81 'is that the yield strength, ultimate tensile strength, elongation and fracture toughness in both the L and LT directions increase as temperature decreases. Although some other aluminum alloys, including 2219-T87, display this behavior [4], 2090-T81 alloy shows a significantly greater improvement in mechanical properties.…”