scholarly journals Mechanical behavior of aluminum-lithium alloys at cryogenic temperatures

1987 ◽  
Vol 18 (10) ◽  
pp. 1695-1701 ◽  
Author(s):  
J. Glazer ◽  
S. L. Verzasconi ◽  
R. R. Sawtell ◽  
J. W. Morris
Keyword(s):  
Mechanical Behavior ◽  
Cryogenic Temperatures ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys

The Effect of Precipitation Aging on the Mechanical Behavior and Microstructure of Aluminum-Lithium Alloys

2001 ◽  
Author(s):  
James M. Fragomeni
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Size Distribution ◽  
Quantitative Methods ◽  
Direct Consequence ◽  
Interparticle Spacing ◽  
Intermetallic Precipitates ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys

Abstract The effect of variations in microstructure as a consequence of heat treating and aging on the mechanical properties of aluminum-lithium alloys was studied. The thermal treatments and composition were correlated to the microstructure and subsequent mechanical behavior of aluminum-lithium and aluminum-lithium-copper alloys that were solution heat treated and artificially aged for a series of aging times and temperatures. The underaged, peak-aged, and overaged thermal heat treatments were considered in determining the effect of the microstructure and processing on the mechanical properties. Standard ASTM tensile testing of the alloys was performed to determine mechanical properties such as yield strength, ductility, and ultimate tensile strength. Quantitative microscopy of the intermetallic precipitates was performed to related the measured deformation behavior to the microstructural features. Thus, the intermetallic precipitates in the microstructure which impede dislocation motion and control the precipitation strengthening response as a function of aging practice were measured by quantitative methods, and are the basis for controlling the mechanical behavior depending on their size distribution, average size, and interparticle spacing. The microstructure was studied, and measurements were made to determine the size, distribution, and morphology for the intermetallic strengthening precipitates as a function of the processing and composition. For the aluminum-lithium alloys studied, the primary strengthening was a direct consequence of ordered coherent Al3Li intermetallic precipitates which were uniformly distributed throughout the microstructure, which restricted the glide motion of dislocations during plastic deformation.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

Deformation and fracture behavior of an Al-Li-Cu-Mg-Zr alloy 8090

1990 ◽  
Vol 48 (4) ◽  
pp. 974-975
Author(s):  
D.M. Jiang ◽  
B.D. Hong
Keyword(s):  
High Strength ◽  
Deformation And Fracture ◽  
Fracture Behaviors ◽  
Aluminum Lithium ◽  
Carbon Fiber Reinforced Composites ◽  
Peak Aged ◽  
Aluminum Lithium Alloys ◽  
High Strength Aluminum Alloys ◽  
Lithium Alloys ◽  
Zr Alloy

Aluminum-lithium alloys have been recently got strong interests especially in the aircraft industry. Compared to conventional high strength aluminum alloys of the 2000 or 7000 series it is anticipated that these alloys offer a 10% increase in the stiffness and a 10% decrease in density, thus making them rather competitive to new up-coming non-metallic materials like carbon fiber reinforced composites.The object of the present paper is to evaluate the inluence of various microstructural features on the monotonic and cyclic deformation and fracture behaviors of Al-Li based alloy. The material used was 8090 alloy. After solution treated and waster quenched, the alloy was underaged (190°Clh), peak-aged (190°C24h) and overaged (150°C4h+230°C16h). The alloy in different aging condition was tensile and fatigue tested, the resultant fractures were observed in SEM. The deformation behavior was studied in TEM.

Lithium depletion during heat treatment of aluminum-lithium alloys

1986 ◽  
Vol 17 (4) ◽  
pp. 635-643 ◽  
Author(s):  
J. M. Papazian ◽  
R. L. Schulte ◽  
P. N. Adler
Keyword(s):  
Heat Treatment ◽  
Aluminum Lithium ◽  
Lithium Depletion ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys

Microanalysis of precipitates in aluminum-lithium alloys with a scanning ion microprobe

1989 ◽  
Vol 37 (1) ◽  
pp. 78-94 ◽  
Author(s):  
D.B. Williams ◽  
R. Levi-Setti ◽  
J.M. Chabala ◽  
Y.L. Wang ◽  
D.E. Newbury
Keyword(s):  
Ion Microprobe ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys

scholarly journals DEVELOPMENT OF A TECHNOLOGICAL PROCESS FOR MANUFACTURING WELDED STRUCTURES

2021 ◽  
Vol 4 (5) ◽  
pp. 35-44
Author(s):  
R. El'cov
Keyword(s):  
Phase Composition ◽  
Laser Welding ◽  
Strain Amplitude ◽  
Welded Joints ◽  
Structural Phase ◽  
Diagnostic Methods ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
First Time ◽  
Lithium Alloys

the main goal of this article is to obtain welded permanent joints of modern thermally hardened aluminum and aluminum-lithium alloys made by laser welding, having mechanical characteristics (temporary tensile resistance, yield strength, elongation at break) and structural-phase composition close to or equal to the base alloy. It is shown for the first time that by controlling the parameters of heat treatment of samples with a welded joint of all studied aluminum-lithium alloys, it is possible to purposefully influence the formation of the specified mechanical properties of the weld by changing the structural and phase composition of the weld. The evolution of the struc-tural and phase composition of welded joints of thermally hardened aluminum and aluminum-lithium alloys has been investigated using modern independent diagnostic methods: for the first time, the use of synchrotron radia-tion diffractometry in combination with high-resolution transmission, scanning electron and optical microscopy. The dependences of the increment of deformation under cyclic loading with amplitudes exceeding the elastic limit on temperature are established. For untreated welded joints, it was found that at +85 C, the inhomogeneity of the deformation increment increases, and its speed increases by 8 times for alloy 1461, 5 times for alloy 1420 and 1.5 times for alloy 1441. At a temperature of -60 0C, alloys 1420 and 1461 have hardening stages, during which the value of deformation decreases at given boundary stress values. At +20 0C, there is a uniform increment of defor-mation and an increase in the amplitude of deformation with an increase in the amplitude of stress. At +85 0C, the strain amplitude does not change with increasing stress amplitude, its value is 0.55-0.5 of the strain amplitude at +20 0C. Based on the research results, technological techniques have been developed that allow obtaining me-chanical characteristics and structural-phase compositions of welded joints close to the main alloy during laser welding of aviation thermally hardened aluminum and aluminum-lithium alloys of the Al-Mg-Cu. Al-Mg-Li, Al-Cu-Mg-Li, Al-Cu-Li systems.

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