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Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320 

443-757-5802 

The use of trademarks or names of manufacturers in this report is for accurate reporting and does not 

constitute an official endorsement, either expressed or implied, of such products or manufacturers by the 

National Aeronautics and Space Administration. 
Contents

List of Tables ............................................................................................................................................... iv

List of Figures ............................................................................................................................................... v

Symbols and Abbreviations ....................................................................................................................... viii

Abstract ......................................................................................................................................................... 1

1. Introduction ........................................................................................................................................... 1

2. Material ................................................................................................................................................. 1

2.1. Microstructure ............................................................................................................................... 2

2.2. Texture Analysis ........................................................................................................................... 5

2.3. Hardness ........................................................................................................................................ 5

2.4. Thermal Analysis .......................................................................................................................... 6

3. Liquid Oxygen Compatibility Testing .................................................................................................. 8

4. Tensile Testing ...................................................................................................................................... 9

5. Compression Testing .......................................................................................................................... 12

6. Fracture Toughness ............................................................................................................................. 14

7. Conclusions ......................................................................................................................................... 16

8. References ........................................................................................................................................... 16

Appendix A: Mill Certifications of 2050 Plate Used in this Study ............................................................. 18

Appendix B: Individual Tensile, Compression and Fracture Toughness Test Data for 4 inch thick 

2050-T84 Plate ............................................................................................................................................ 22

Appendix C: Individual Stress-Strain Curves for Tensile Tests on 4 inch thick 2050-T84 Plate ............... 27

Appendix D: Individual Stress-Strain Curves for Compression Tests on 4 inch thick 2050-T84 Plate ..... 52
iv

List of Tables

Table 1. Composition of 2050 Plates Used in this Study Compared to AMS 4413 (ref. 3) Specification 

Range (weight percent) ............................................................................................................... 2

Table 2. Through-Thickness Variation in Composition of 4 inch 2050 Plate (weight percent) ............... 2

Table 3. Measured Mean and Standard Deviation VHN Hardness Values Across Duplicate Scans on 

2050-T84 Plate ............................................................................................................................ 6

Table 4. Peak Temperatures in the Cp Curves at Various Locations in the 2 inch and 4 inch thick Plates 

of 2050-T84 ................................................................................................................................ 8

Table 5. 2050 Promoted Combustion Test Results (Test 17) ................................................................... 9

Table 6. 2050 Mechanical Impact Test Results (Tests 13A and 13B) ...................................................... 9

Table 7. A-Basis Tensile Properties of 4 inch thick 2050-T84 Plate (ref. 2, 3) ...................................... 11

Table 8. Average Ambient Temperature Tensile Results for 4 inch thick 2050-T84 Plate .................... 11

Table 9. Average Cryogenic Temperature Tensile Results for 4 inch thick 2050-T84 Plate ................. 12

Table 10. Typical Tensile Properties of 1.85 inch thick 2195-T8 Plate (ref. 16) ...................................... 12

Table 11. A-Basis Compressive Properties of 4 inch thick 2050-T84 Plate (ref. 2) ................................. 13

Table 12. Average Compression Test Results for 4 inch thick 2050-T84 Plate ....................................... 13

Table 13. Typical Compression Properties of 1.85 inch thick 2195-T8 Plate (ref. 16) ............................ 14

Table 14. Fracture Toughness of 4 inch thick 2050-T84 Plate at Ambient and Cryogenic Temperatures 16

Table B1. 2050-T84 Ambient Temperature (75°F) Tensile Results .......................................................... 22

Table B2. 2050-T84 Cryogenic Temperature (-320°F) Tensile Results .................................................... 23

Table B3. 2050-T84 Ambient Temperature (75°F) Compression Results ................................................ 24

Table B4. 2050-T84 Cryogenic Temperature (-320°F) Compression Results .......................................... 25

Table B5. 2050-T84 Ambient Temperature (75°F) Fracture Toughness Results ...................................... 26

Table B6. 2050-T84 Cryogenic Temperature (-320°F) Fracture Toughness Results ................................ 26
v 

List of Figures

Figure 1. Microstructure of 2 inch thick 2050-T84 plate at three through thickness locations: (a) t/6, 

(b) t/2, (c) 5t/6. ......................................................................................................................... 3

Figure 2. Microstructure of 4 inch thick 2050-T84 plate at three through thickness locations: (a) t/6, 

(b) t/2, (c) 5t/6. ......................................................................................................................... 4

Figure 3. Microstructure of 4 inch thick 2050-T84 plate at three through thickness locations, near 

surface (to), t/4, and t/2, rotated 45 degrees using cross-polarized illumination. ..................... 4

Figure 4. Through-thickness variation in the intensity of selected texture components in 4 inch thick 

2050-T84 plate: (a) deformation and (b) recrystallization. ...................................................... 5

Figure 5. Through-thickness variation in hardness of the 2 inch and 4 inch thick 2050-T84 plates. ...... 6

Figure 6. Tentative phase identification of thermal events in the Cp curve for 2050-T84 plate. ............ 7

Figure 7. Specific heat curves for the 2 inch and 4 inch thick 2050-T84 plates. .................................... 7

Figure 8. Tensile specimen (all dimensions in inches). (ref. 15) ............................................................ 9

Figure 9. Diagram of tensile and compression specimen orientations extracted from 4 inch thick 2050-

T84 plate. ............................................................................................................................... 10

Figure 10. Compact tension specimen (all dimensions in inches). ......................................................... 15

Figure 11. Compact tension specimen orientation with respect to plate. ................................................ 15

Figure C1. Tensile data for 2050-T84, L orientation, t/6, specimen 1, tested at 75oF. ......................... 27

Figure C2. Tensile data for 2050-T84, L orientation, t/6, specimen 2, tested at 75oF. ......................... 28

Figure C3. Tensile data for 2050-T84, L orientation, t/6, specimen 3, tested at 75oF. ......................... 28

Figure C4. Tensile data for 2050-T84, L orientation, t/2, specimen 1, tested at 75oF. ......................... 29

Figure C5. Tensile data for 2050-T84, L orientation, t/2, specimen 2, tested at 75oF. ......................... 29

Figure C6. Tensile data for 2050-T84, L orientation, t/2, specimen 3, tested at 75oF. ......................... 30

Figure C7. Tensile data for 2050-T84, LT orientation, t/6, specimen 1, tested at 75oF. ....................... 30

Figure C8. Tensile data for 2050-T84, LT orientation, t/6, specimen 2, tested at 75oF. ....................... 31

Figure C9. Tensile data for 2050-T84, LT orientation, t/6, specimen 3, tested at 75oF. ....................... 31

Figure C10. Tensile data for 2050-T84, LT orientation, t/2, specimen 1, tested at 75oF. ....................... 32

Figure C11. Tensile data for 2050-T84, LT orientation, t/2, specimen 2, tested at 75oF. ....................... 32

Figure C12. Tensile data for 2050-T84, LT orientation, t/2, specimen 3, tested at 75oF. ....................... 33

Figure C13. Tensile data for 2050-T84, ST orientation, t/2, specimen 1, tested at 75oF. ....................... 33

Figure C14. Tensile data for 2050-T84, ST orientation, t/2, specimen 2, tested at 75oF. ....................... 34

Figure C15. Tensile data for 2050-T84, ST orientation, t/2, specimen 3, tested at 75oF. ....................... 34

Figure C16. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 1, tested at 75oF. ................. 35

Figure C17. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 2, tested at 75oF. ................. 35

Figure C18. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 3, tested at 75oF. ................. 36
vi

Figure C19. Tensile data for 2050-T84, 45o orientation, t/6, specimen 1, tested at 75oF. ...................... 36

Figure C20. Tensile data for 2050-T84, 45o orientation, t/6, specimen 2, tested at 75oF. ...................... 37

Figure C21. Tensile data for 2050-T84, 45o orientation, t/6, specimen 3, tested at 75oF. ...................... 37

Figure C22. Tensile data for 2050-T84, 45o orientation, t/2, specimen 1, tested at 75oF. ...................... 38

Figure C23. Tensile data for 2050-T84, 45o orientation, t/2, specimen 2, tested at 75oF. ...................... 38

Figure C24. Tensile data for 2050-T84, 45o orientation, t/2, specimen 3, tested at 75oF. ...................... 39

Figure C25. Tensile data for 2050-T84, L orientation, t/6, specimen 4, tested at -320oF. ...................... 39

Figure C26. Tensile data for 2050-T84, L orientation, t/6, specimen 5, tested at -320oF. ...................... 40

Figure C27. Tensile data for 2050-T84, L orientation, t/6, specimen 6, tested at -320oF. ...................... 40

Figure C28. Tensile data for 2050-T84, L orientation, t/6, specimen 7, tested at -320oF. ...................... 41

Figure C29. Tensile data for 2050-T84, L orientation, t/2, specimen 4, tested at -320oF. ...................... 41

Figure C30. Tensile data for 2050-T84, L orientation, t/2, specimen 5, tested at -320oF. ...................... 42

Figure C31. Tensile data for 2050-T84, L orientation, t/2, specimen 6, tested at -320oF. ...................... 42

Figure C32. Tensile data for 2050-T84, LT orientation, t/6, specimen 4, tested at -320oF. ................... 43

Figure C33. Tensile data for 2050-T84, LT orientation, t/6, specimen 5, tested at -320oF. ................... 43

Figure C34. Tensile data for 2050-T84, LT orientation, t/6, specimen 6, tested at -320oF. ................... 44

Figure C35. Tensile data for 2050-T84, LT orientation, t/2, specimen 4, tested at -320oF. ................... 44

Figure C36. Tensile data for 2050-T84, LT orientation, t/2, specimen 5, tested at -320oF. ................... 45

Figure C37. Tensile data for 2050-T84, LT orientation, t/2, specimen 6, tested at -320oF. ................... 45

Figure C38. Tensile data for 2050-T84, ST orientation, t/2, specimen 4, tested at -320oF. .................... 46

Figure C39. Tensile data for 2050-T84, ST orientation, t/2, specimen 5, tested at -320oF. .................... 46

Figure C40. Tensile data for 2050-T84, ST orientation, t/2, specimen 6, tested at -320oF. .................... 47

Figure C41. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 4, tested at -320oF. ............. 47

Figure C42. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 5, tested at -320oF. ............. 48

Figure C43. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 6, tested at -320oF. ............. 48

Figure C44. Tensile data for 2050-T84, 45o orientation, t/6, specimen 4, tested at -320oF. ................... 49

Figure C45. Tensile data for 2050-T84, 45o orientation, t/6, specimen 5, tested at -320oF. ................... 49

Figure C46. Tensile data for 2050-T84, 45o orientation, t/6, specimen 6, tested at -320oF. ................... 50

Figure C47. Tensile data for 2050-T84, 45o orientation, t/2, specimen 5, tested at -320oF. ................... 50

Figure C48. Tensile data for 2050-T84, 45o orientation, t/2, specimen 6, tested at -320oF. ................... 51

Figure C49. Tensile data for 2050-T84, 45o orientation, t/2, specimen 7, tested at -320oF. ................... 51

Figure D1. Compression data for 2050-T84, L orientation, t/2, specimen 1, tested at 75oF. ................ 52

Figure D2. Compression data for 2050-T84, L orientation, t/2, specimen 2, tested at 75oF. ................ 53

Figure D3. Compression data for 2050-T84, L orientation, t/2, specimen 3, tested at 75oF. ................ 53
vii

Figure D4. Compression data for 2050-T84, L orientation, t/6, specimen 1, tested at 75oF. ................ 54

Figure D5. Compression data for 2050-T84, L orientation, t/6, specimen 3, tested at 75oF. ................ 54

Figure D6. Compression data for 2050-T84, L orientation, t/6, specimen 4, tested at 75oF. ................ 55

Figure D7. Compression data for 2050-T84, LT orientation, t/2, specimen 1, tested at 75oF............... 55

Figure D8. Compression data for 2050-T84, LT orientation, t/2, specimen 2, tested at 75oF............... 56

Figure D9. Compression data for 2050-T84, LT orientation, t/2, specimen 3, tested at 75oF............... 56

Figure D10. Compression data for 2050-T84, LT orientation, t/6, specimen 1, tested at 75oF............... 57

Figure D11. Compression data for 2050-T84, LT orientation, t/6, specimen 2, tested at 75oF............... 57

Figure D12. Compression data for 2050-T84, LT orientation, t/6, specimen 3, tested at 75oF............... 58

Figure D13. Compression data for 2050-T84, 45o orientation, t/2, specimen 1, tested at 75oF. ............. 58

Figure D14. Compression data for 2050-T84, 45o orientation, t/2, specimen 2, tested at 75oF. ............. 59

Figure D15. Compression data for 2050-T84, 45o orientation, t/2, specimen 3, tested at 75oF. ............. 59

Figure D16. Compression data for 2050-T84, 45o orientation, t/6, specimen 1, tested at 75oF. ............. 60

Figure D17. Compression data for 2050-T84, 45o orientation, t/6, specimen 2, tested at 75oF. ............. 60

Figure D18. Compression data for 2050-T84, 45o orientation, t/6, specimen 3, tested at 75oF. ............. 61

Figure D19. Compression data for 2050-T84, L orientation, t/2, specimen 4, tested at -320oF. ............. 61

Figure D20. Compression data for 2050-T84, L orientation, t/2, specimen 5, tested at -320oF. ............. 62

Figure D21. Compression data for 2050-T84, L orientation, t/2, specimen 6, tested at -320oF. ............. 62

Figure D22. Compression data for 2050-T84, L orientation, t/6, specimen 2, tested at -320oF. ............. 63

Figure D23. Compression data for 2050-T84, L orientation, t/6, specimen 5, tested at -320oF. ............. 63

Figure D24. Compression data for 2050-T84, L orientation, t/6, specimen 6, tested at -320oF. ............. 64

Figure D25. Compression data for 2050-T84, LT orientation, t/2, specimen 4, tested at -320oF. .......... 64

Figure D26. Compression data for 2050-T84, LT orientation, t/2, specimen 5, tested at -320oF. .......... 65

Figure D27. Compression data for 2050-T84, LT orientation, t/2, specimen 6, tested at -320oF. .......... 65

Figure D28. Compression data for 2050-T84, LT orientation, t/6, specimen 4, tested at -320oF. .......... 66

Figure D29. Compression data for 2050-T84, LT orientation, t/6, specimen 5, tested at -320oF. .......... 66

Figure D30. Compression data for 2050-T84, LT orientation, t/6, specimen 6, tested at -320oF. .......... 67

Figure D31. Compression data for 2050-T84, 45o orientation, t/2, specimen 4, tested at -320oF. .......... 67

Figure D32 Compression data for 2050-T84, 45o orientation, t/2, specimen 5, tested at -320oF. .......... 68

Figure D33. Compression data for 2050-T84, 45o orientation, t/2, specimen 6, tested at -320oF. .......... 68

Figure D34. Compression data for 2050-T84, 45o orientation, t/6, specimen 4, tested at -320oF. .......... 69

Figure D35. Compression data for 2050-T84, 45o orientation, t/6, specimen 5, tested at -320oF. .......... 69

Figure D36. Compression data for 2050-T84, 45o orientation, t/6, specimen 6, tested at -320oF. .......... 70
viii

Symbols and Abbreviations

Al aluminum 

Al-Li aluminum-lithium

AMS Aerospace Material Specification

ASTM American Society for Testing and Materials

°C temperature, degrees Celsius

C(T) compact tension specimen

Cp temperature-dependent specific heat

DSC differential scanning calorimetry

eT total elongation, measured in % 

E Young’s modulus in tension, measured in Msi 

Ec Young’s modulus in compression, measured in Msi 

°F temperature, degrees Fahrenheit

Fcy 0.2% offset compression yield strength, measured in ksi 

Ftu ultimate tensile strength, measured in ksi

Fty 0.2% offset tension yield strength, measured in ksi

Hz Hertz, cycles per second

ipm inches per minute 

ksi 1,000 pounds/in2

KQJIC conditional fracture toughness, measured in ksi√in

L direction parallel to plate rolling direction

LN2 liquid nitrogen

LOX liquid oxygen 

L-S denotes fracture plane normal to L with crack propagation in ST 

L-T denotes fracture plane normal to L with crack propagation in LT

LT direction perpendicular to rolling direction

L45ST direction 45° from the L direction in the ST plane 

micron 10-6 meters

mli mean lineal intercept, method of measuring approximate grain dimensions 

Msi 1,000,000 pounds/in2

μm micrometers

ODF orientation distribution function

psia absolute pressure, pounds per square inch

RT room temperature, approximated as 75°F 

SD standard deviation

ST direction perpendicular to L and LT

t thickness, measured in inches

t0 thickness position near plate surface

t/6, 5t/6 plane 1/6 from either surface of plate 

t/2 through thickness midplane of plate 

TEM transmission electron microscopy

T-L denotes fracture plane normal to LT with crack propagation in L 

VHN Vickers hardness number
Abstract

Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the 

mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of 

the incumbent aluminum alloy, 2195, which will enable designs with greater structural efficiency. While 

ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are 

not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and 

fracture tests were conducted on 4 inch thick 2050–T84 plate at ambient temperature and at -320°F. 

Various metallurgical analyses were also performed in order to provide an understanding of the 

compositional homogeneity and microstructure of 2050. 

1. Introduction

Aluminum alloy 2050 is an aluminum-copper-lithium alloy produced by Alcan Global Aerospace. The

alloy was designed to provide improvements in strength, toughness, elastic modulus and fatigue crack 

growth resistance, together with a reduction in density, as compared to conventional non-lithium bearing 

2XXX and 7XXX series alloys (refs. 1, 2, 3, 4). The alloy also exhibits excellent stress corrosion cracking 

resistance and is weldable. It is available in plate thicknesses from 0.5 to 5.0 inches.

Launch vehicle cryogenic propellant tanks typically employ integrally stiffened skins, a structural design 

that requires extensive machining of thick plate for fabrication. Recent design studies (ref. 5) have 

indicated significant mass reduction for future heavy lift launch vehicle cryogenic propellant tanks 

through the use of taller, more widely spaced stiffening elements to optimize structural design. However, 

the maximum available plate thickness of the current cryogenic tank alloy, 2195, is 1.95 inches, thus 

limiting the tank stiffener height to less than 2 inches. This thickness limitation is due to the quench rate 

senstivity of the alloy (ref. 6) which gives rise to inhomogeneity and a drop in properties. In contrast, 

2050 is reported to be significantly less quench sensitive, retaining uniform strength and toughness 

properties in thicknesses up to 5 inches. Room temperature mechanical properties and density (0.098 

lbs/in3

) of 2050 are similar to those of 2195 (ref. 2, 4); however, no cryogenic temperature mechanical 

properties are presently available for 2050. Thus, a study was undertaken to measure mechanical 

properties of 2050 including tensile strength, compression strength and fracture toughness at ambient and 

cryogenic temperatures; characterize its microstructure via optical microscopy, orientation distribution 

function (ODF) x-ray texture analysis and differential scanning calorimetry (DSC); and determine the 

liquid oxygen compatibility of the alloy.

2. Material

Two plates of 2050 from two different lots of material were procured to AMS 4413 specifications (ref. 3). 

One 2 inch thick plate in the –T84 temper (44 inches by 30 inches by 2 inches, lot number 805751) was 

used for liquid oxygen compatibility testing. One 4 inch thick plate in the –T84 temper (120 inches by 64 

inches by 4 inches, lot number 278111) was used for all mechanical property testing and metallography. 

The chemical compositions of the two plates, as provided on the mill certifications, are presented in Table 

1, along with the AMS specification range for this alloy (ref. 3). The mill certifications for the plates are 

included in Appendix A. The compositions of both plates were within the AMS specification. Throughthickness chemical analysis was performed using direct current plasma spectroscopy at two lengthwise 

locations in the 4 inch thick plate. Results shown in Table 2 for positions near the plate surface (to), t/4, 

and t/2 indicated uniform composition throughout the plate.
2 

Table 1. Composition of 2050 Plates Used in this Study Compared to AMS 4413 (ref. 3)

Specification Range (weight percent) 

Plate 

Thickness Lot Al Cu Li Mg Mn Ag Zr Si Fe Zn

2 in. 805751 Bal. 3.56 0.88 -- 0.38 0.35 0.10 0.03 0.05 --

4 in. 278111 Bal. 3.48 0.90 0.34 0.36 0.36 0.09 0.03 0.05 0.01 

AMS 

4413 Min. 3.20 0.70 0.20 0.20 0.20 0.06 -- -- --

AMS 

4413 Max. 3.90 1.30 0.60 0.50 0.70 0.14 0.08 0.10 0.25 

Table 2. Through-Thickness Variation in Composition of 4 inch 2050 Plate (weight percent) 

Cu Li Mg Mn Ag Zr

Location 

#1 

to 3.35 0.80 0.31 0.33 0.33 0.09

t/4 3.41 0.83 0.32 0.33 0.32 0.11

t/2 3.32 0.85 0.31 0.33 0.33 0.08

Location 

#2 

to 3.41 0.82 0.31 0.34 0.33 0.12

t/4 3.30 0.83 0.31 0.32 0.33 0.09

t/2 3.38 0.81 0.31 0.33 0.34 0.09

2.1. Microstructure

Microstructure of the 2 inch and 4 inch 2050-T84 plates was evaluated in the three principal planes, i.e., 

normal to L, LT, and ST. In addition, these microstructures were examined at three through thickness 

locations, t/6, t/2 and 5t/6 to evaluate through-thickness variability. Specimens extracted from these 

locations were mounted, polished, and then anodized using Barker’s reagent and examined under crosspolarized illumination. Micrographs for the 2 inch thick plate are presented in Figure 1; those for the 4 

inch thick plate are presented in Figure 2. 

The grain morphology observed in both the 2 inch and 4 inch plates was elongated and lamellar, typical 

of rolled Al-Li plate. As expected, the grain aspect ratio was larger in the 2 inch plate than in the 4 inch 

plate at all through-thickness positions due to the greater reduction in thickness experienced by the 2 inch 

plate during rolling. 

During cross-polarized imaging, the anodized specimens were rotated 45° in order to maximize contrast 

in the microstructures being observed. The resulting micrographs for the 4 inch plate in the L-S and T-S 

planes are presented in Figure 3. These images revealed a largely unrecrystallized microstructure with 

high aspect ratio grain morphology (approximately L:T=2.5:1 and L:S=10:1), with evidence of some substructure present. The microstructure was uniform both parallel (L-S) and perpendicular (T-S) to the 

rolling direction (L). Approximate grain dimensions, based on the mean lineal intercept (mli) method, 

were 500 μm in the L direction, 200 μm in the T direction, and 50 μm in the S direction. 
3 

(a) (b) 

(c) 

Figure 1. Microstructure of 2 inch thick 2050-T84 plate at three through thickness locations: (a) t/6, 

(b) t/2, (c) 5t/6.
4 

(a) (b) 

(c) 

Figure 2. Microstructure of 4 inch thick 2050-T84 plate at three through thickness locations: (a) t/6, 

(b) t/2, (c) 5t/6.

Figure 3. Microstructure of 4 inch thick 2050-T84 plate at three through thickness locations, near 

surface (to), t/4, and t/2, rotated 45 degrees using cross-polarized illumination.
5 

2.2. Texture Analysis

X-ray texture analysis using Orientation Distribution Functions (ODF) of the 4 inch thick plate was 

performed to correlate crystallographic texture characteristics and the observed grain morphologies with

the measured mechanical properties. ODF plots were derived from the texture components obtained from 

more basic x-ray pole figures corresponding to the [111], [200], and [311] x-ray reflections of the 

aluminum matrix (ref. 7). Samples for this analysis were measured at various locations through the 

thickness of the 4 inch plate. The results presented in Figure 4 show variations in the intensities of texture 

components through the plate thickness direction. The types of texture components and their spatial 

distribution are typical of those documented for aluminum alloys in plate forms subjected to cold 

deformation and/or recrystallization anneals (ref. 8, 9). 

In Figure 4a, many of the deformation components were particularly strong through the midplane region, 

reflecting the overlapping strain fields during rolling deformation. Intensities of all deformation 

components were weak between t/4 and t/8. Intensities of some of the recrystallization components, 

shown in Figure 4b, were strongest at t/2, though of lower intensity than those of the deformation 

components. Other recrystallization texture components exhibited moderate intensity peaks between t/4 

and t/8, that were weaker at t/2. 

(a) (b)

Figure 4. Through-thickness variation in the intensity of selected texture components in 4 inch thick 

2050-T84 plate: (a) deformation and (b) recrystallization.

2.3. Hardness

Hardness may be used as an indication of strength in ductile metals, and determination of its distribution 

in a product form may be used to assess compositional or microstructural homogeneity of the alloy. 

Through-thickness hardness measurements were performed on cross-sections of both the 2 inch and 4 

inch plates, employing a Vickers indenter with a 2000 gram load. Full surface-to-surface hardness scans 

were performed on the 2 inch plate, while only surface-to-mid-plane scans were performed on the 4 inch 

plate. Duplicate hardness profiles (scan #1 and scan #2) for each plate, shown in Figure 5, revealed 

uniform through-thickness hardness throughout both plates. The mean hardness values were essentially 

identical for both plates, as summarized in Table 3. The uniformity in the hardness data and similarity in 

values for both plates indicates a high degree of microstructural homogeneity throughout each of the 2 

inch and 4 inch plates examined.

0

5

10

15

20

25

30

35

40

t=0 t/8 t/4 3t/8 t/2 3t/8 t/4 t/8 t=0

ODF Intensity

Bs

S

S'1

S'2

Cu

Ex1

Ex2

Ex3

Shear1

Shear2

Shear3

0

1

2

3

4

5

6

t=0 t/8 t/4 3t/8 t/2 3t/8 t/4 t/8 t=0

ODF Intensity

Goss

Cube

RCrd1

RCrd2

RCnd1

RCnd2

P

Q

R

BsRX
6 

Table 3. Measured Mean and Standard Deviation VHN Hardness Values Across Duplicate Scans 

on 2050-T84 Plate

Plate Thickness VHN, Scan #1 VHN, Scan #2

2 in. 140.9±3.5 140.5±4.1

4 in. 140.6±3.5 140.7±3.5

Figure 5. Through-thickness variation in hardness of the 2 inch and 4 inch thick 2050-T84 plates. 

2.4. Thermal Analysis 

Temperature-dependent specific heat (Cp) of an alloy is a function of composition, homogeneity, and 

precipitate microstructure. Differential scanning calorimetry (DSC) is a sensitive technique for Cp

measurements in aerospace aluminum alloys. Together with transmission electron microscopy (TEM), 

DSC enables identification of alloy tempers, relative volume fractions of various stable and metastable 

phases in the microstructure, and evaluation of compositional or microstructural inhomogeneities. 

Employing a heating rate of 18°F/min (10°C/min) in flowing nitrogen gas, samples were scanned from 

room temperature (RT) to 1022°F (550°C). Cp measurements were made using the 3-Curve Ratio method 

described in ASTM E1269 (ref. 10), using a sapphire standard. Duplicate samples were tested for both the 

2 inch and the 4 inch plates from selected through-thickness locations. 

At least seven thermal events are noted in the Cp versus temperature curve; these are identified in Figure 6

based on compositional and temper similarity of 2050 to 2195. The Cp curves for the 2 inch plate at t/8 

and t/2 and for the 4 inch plate at t/8, t/4, and t/2 are shown in Figure 7. The temperature peaks from 

duplicate DSC runs are presented in Table 4, where the thermal events are referenced to Figure 6. These 

Cp curves are similar within +5% (the instrument’s limit of repeatability), including the occurrence of 

peaks and their associated temperatures as shown in Table 4. These results imply that alloy chemistries 

and precipitate microstructures are uniform throughout the thickness of each plate and that the 2 inch 

plate and 4 inch plates are chemically and microstructurally similar.

100

110

120

130

140

150

0 0.5 1 1.5 2

Hardness, VHN2000gf

Distance, in.

AA2050, 2", scan#1

AA2050, 2", scan#2

AA2050, 4", scan#1

AA2050, 4", scan#2
7 

Figure 6. Tentative phase identification of thermal events in the Cp curve for 2050-T84 plate.

Figure 7. Specific heat curves for the 2 inch and 4 inch thick 2050-T84 plates. 

(7a & 7b) Complex

dissolution endotherm

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

50 100 150 200 250 300 350 400 450 500 550

(1) δ′ dissolution

(2) T1 dissolution

(3) T1 re-precipitation

(4) T1 dissolution 

+

θ′ precipitation

Cp, J/g.K

°C

(5) θ′ precipitation

(6) θ′ dissolution

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

50 100 150 200 250 300 350 400 450 500 550

Cp, J/g·K

Temperature, °C

Run 1: 4" Plate, t/8

Run 1a: 4" Plate, t/8

Run 2: 4" Plate, t/4

Run 2a: 4" Plate, t/4

Run 3: 4" Plate, t/2

Run 3a: 4" Plate, t/2

Run 4: 2" Plate, t/8

Run 4a: 2" Plate, t/8

Run 5: 2" Plate, t/2

Run 5a: 2" Plate, t/2
8 

Table 4. Peak Temperatures in the Cp Curves at Various Locations in the 2 inch and 4 inch thick 

Plates of 2050-T84

Thermal 

Event 2 in., t/8 2 in., t/2 4 in., t/8 4 in., t/4 4 in., t/2 2 in. Avg. ± SD

4 in. Avg. ± 

SD

1 103.4

102.5

96.4

102.8

105.8

103.5

100.7

100.2

104.8

102.3 103.1±0.4 104.1±2.5 

2 212.4

213.5

219.4

213.8

213.8

213.5

215.7

214.2

220.8

219.3 213.1±1.0 216.5±3.9 

3 295.4

297.5

298.4

297.8

297.8

297.5

296.7

295.2

297.8

295.3 296.6±1.7 296.6±1.7 

4 323.4

323.5

325.4

325.8

324.8

324.5

323.7

323.2

324.8

323.3 324.6±1.7 324.8±1.1 

5 341.4

342.5 

345.4

344.8 

341.8

341.5 

340.7

340.2 

342.8

341.3 343.1±2.4 341.6±0.4 

6 357.4

358.5

359.4

359.8

357.8

357.5

356.7

356.2

358.8

356.3 358.6±1.7 357.6±1.1 

7a 410.4

411.5

411.4

410.8

414.8

412.5

407.7

410.2

410.8

408.3 410.6±0.3 411.6±4.6 

7b 456.4

456.5

452.4

451.8

458.8

460.5

459.7

459.2

455.8

457.3 454.1±3.3 458.1±1.1 

3. Liquid Oxygen Compatibility Testing

In order to use a material in the presence of high concentrations of oxygen, it must be evaluated per 

NASA-STD-(I)-6001B - Flammability, Offgassing, And Compatibility Requirements And Test 

Procedures (ref. 11) and NASA-STD-6016 - Standard Materials And Processes Requirements For 

Spacecraft (ref. 12). Oxygen compatibility testing was conducted by the Materials Test Branch (EM10) at 

NASA’s George C. Marshall Space Flight Center. The tests conducted per NASA-STD-6001 included 

Test 17 (Promoted Ignition-Combustion (Upward Flammability of Metals)) and Tests 13A and 13B 

(Ambient Pressure and High Pressure Liquid Oxygen Mechanical Impact).

Specimens were extracted from the 2 inch 2050-T84 plate. Specimens for Test 17 consisted of rectangular 

bars 0.126 inch by 0.126 inch by 4 inches. This alternate specimen geometry was used due to difficulty in 

machining the primary 0.126 inch diameter specimen with a length of 6-12 inches. Specimens were 

cleaned per ASTM G86 (ref. 13) to remove any contaminants that could affect the test results. A 0.38 

gram titanium promoter was attached to the end of the specimen which was then installed in the test 

chamber. The test chamber was sealed, purged several times with pure oxygen, then pressurized to the 

desired test conditions. An aluminum-palladium igniter wire was used to ignite the promoter. After the 

test, the unburned length of specimen was recorded. 

Specimens for Tests 13A and 13B were discs 0.69 inch diameter by 0.127 inch thick. Prior to testing, the 

specimens were cleaned per ASTM G86 (ref. 13) to remove any contaminants that could affect the test 

results. The specimen was inserted into the test cup, installed in the test apparatus and immersed in liquid 

oxygen at the desired pressure. The specimens were then impacted with an energy of 72 ft·lbf and 

observed for signs of ignition such as flash, char marks, etc.

All specimens burned during Test 17; however, at most pressures tested, the specimens self-extinguished 

before they were completely consumed. Average burn lengths for each tested pressure are presented in 

Table 5. For the mechanical impact Tests 13A and 13B, no reactions were observed at the three 
9 

conditions tested; results are summarized in Table 6. These initial results indicate that 2050 compares 

favorably with current cryogenic tank alloys 2195 and 2219 (ref. 14). 

Table 5. 2050 Promoted Combustion Test Results (Test 17) 

Pressure (psia) Burn Length (in.)

50 0.84

60 0.86

75 0.75

100 1.33

125 0.81

150 1.90

160 2.39

170 3.38

180 4.12 (total burn)

190 1.81

200 1.75

210 1.79

226 4.12 (total burn)

250 4.12 (total burn)

300 4.12 (total burn)

Table 6. 2050 Mechanical Impact Test Results (Tests 13A and 13B) 

LOX Pressure (psia) Reactions/Tests

14.7 0/20

300 0/20

400 0/20

4. Tensile Testing

Tensile tests were conducted per ASTM E8-09 (ref. 15), using sub-size round specimens with a test 

section diameter of 0.250 inches as illustrated in Figure 8. Specimens were extracted from t/6 and t/2 

locations from the 4 inch 2050 plate in the following orientations: L, LT, 45, ST (t/2 only) and L45ST (t/2 

only), as shown in Figure 9 . Testing was conducted using a servohydraulic test stand at a constant 

crosshead speed of 0.010 ipm. Strain was measured using two back-to-back extensometers with a 1.000 

inch gage length. Tests were conducted at ambient temperature (approx. 75°F) in laboratory air and at 

cryogenic temperature (approx. -320°F) immersed in liquid nitrogen. Test data were recorded at 10 Hz. 

Figure 8. Tensile specimen (all dimensions in inches). (ref. 15) 

0.250

0.375

1.25

THREAD BOTH

ENDS 3/8-16

R3/16 TYP 2 PL

2.5
10 

Figure 9. Diagram of tensile and compression specimen orientations extracted from 4 inch thick 

2050-T84 plate.

The published A-Basis tensile properties (ref. 2), which are also the material specification (ref. 3) 

minimum, are presented in Table 7. The average of the three replicate tests is presented in Table 8 for 

ambient temperature tests and in Table 9 for cryogenic temperature tests. The individual test results are 

tabulated in Appendix B and the stress-strain curves are included in Appendix C. 

The ambient temperature tensile properties of the four principal orientations (L, LT, ST and 45°) 

exceeded the published A-Basis mechanical properties for 2050 (ref. 2). Through-thickness location 

dependent variations were noted in the L and LT orientations. In the L orientation, parallel to the rolling 

direction, the specimens machined from the t/2 location had 6-7% higher strengths and 35% lower 

elongation values as compared to the t/6 location. For the LT orientation, tensile strength is 1-3% lower 

and elongation is 25% lower at t/2 than at t/6. However, the 45° orientation showed no variation in 

strength with through-thickness location, although elongation was higher at t/6 than at t/2. The L45ST 

strength and elongation values are the lowest of the orientations tested. 

Examining individual data shown in Appendix B reveals that the standard deviations on these data are 

less than 1%. This anisotropy in the tensile properties is expected, based upon the elongated 

microstructure in the L orientation and the higher intensity deformation texture components in the nearmidplane region of the 4 inch 2050 plate. The anisotropy is attributed to the strain gradients introduced 

into the plate during rolling, resulting in increased strain that occurs nearer to the t/2 location. The lower 

but more isotropic yield strengths at the t/6 location is consistent with the weaker deformation texture 

components calculated in the ODF analysis. 

As 2050 was originally intended for use at ambient temperatures, no cryogenic mechanical property data 

are available for comparison with those obtained in the present study. Specimens in all orientations 

exhibited an increase in strength and modulus as temperature was decreased from ambient temperature to

-320°F. Over the same temperature range, elongation increased for all orientations except LT, for which it 

decreased slightly. Through-thickness variations in properties similar to those observed at ambient 

temperature were also observed at cryogenic temperature.
11 

For comparison, Table 10 shows the typical tensile properties for 1.85 inch thick 2195-T8 plate (ref. 16), 

which is the thickest plate available for 2195 used in current cryotank applications. The strength and 

elongation values for the 4 inch 2050-T84 plate were less than 3% lower than that of 2195-T8, both at 

ambient (75°F) and at cryogenic (-320°F) temperatures. Elongation reductions observed for the LT 

orientation in 2050 at -320°F were similar to those for 2195. 

Table 7. A-Basis Tensile Properties of 4 inch thick 2050-T84 Plate (ref. 2, 3) 

Orient. Fty

(ksi)

Ftu

(ksi)

E

(Msi)

eT

(%)

L 66 71 10.9 6

LT 64 71 10.9 3 

ST 59 69 10.5 1.5

45 65 73 -- - 

Table 8. Average Ambient Temperature Tensile Results for 4 inch thick 2050-T84 Plate

Orient. Plate 

Location 

Fty

(ksi)

Ftu

(ksi)

E

(Msi)

eT

(%)

L t/2 74.6 79.2 11.0 8.8 

t/6 70.6 73.9 10.9 13.8 

LT t/2 67.9 74.8 11.0 8.5 

t/6 69.6 75.7 10.9 11.3

ST t/2 64.2 73.3 10.7 4.8 

45 t/2 65.6 72.4 10.8 9.9 

t/6 65.4 72.8 10.8 12.0 

L45ST t/2 63.1 68.1 10.9 2.5
12 

Table 9. Average Cryogenic Temperature Tensile Results for 4 inch thick 2050-T84 Plate

Orient. Plate 

Location

Fty

(ksi)

Ftu

(ksi)

E

(Msi)

eT

(%)

L t/2 85.9 95.7 12.2 10.7 

t/6 81.5 88.8 11.9 16.9

LT t/2 78.9 91.4 12.3 7.8

t/6 79.9 91.6 12.1 12.3 

ST t/2 73.1 87.3 11.9 5.3 

45 t/2 74.2 86.4 11.8 11.2 

t/6 74.5 86.8 11.6 14.6 

L45ST t/2 73.6 82.3 12.0 3.6 

Table 10. Typical Tensile Properties of 1.85 inch thick 2195-T8 Plate (ref. 16) 

75°F -320°F 

Orient. Fty

(ksi)

Ftu

(ksi)

eT

(%)

Fty

(ksi)

Ftu

(ksi)

eT

(%)

L 76 80 9.0 93 101 10.9 

LT 76 83 8.1 92 104 7.6 

ST 74 86 4.5 81 95 6.4 

45 73 81 9.6 87 99 10.2

5. Compression Testing

Compression tests were conducted per ASTM E9-09 (ref. 17) using cylindrical specimens with a diameter 

of 0.500 inches and a length of 1.5 inches, resulting in a length-to-diameter (L/D) ratio of 3. Specimens 

were extracted from the 4 inch 2050-T84 temper plate at t/6 and t/2 locations in L, LT and 45° 

orientations, similar to the tensile specimens shown in Figure 9. Testing was conducted using a 

servohydraulic test stand at a constant crosshead speed of 0.010 ipm. Strain was measured using two 

back-to-back extensometers with a 1.000 inch gage length. Specimens were loaded to a plastic strain of 

approximately 2%, then unloaded. Tests were conducted at ambient temperature (75°F) in laboratory air 

and at cryogenic temperature (-320°F) immersed in liquid nitrogen. Test data were recorded at 10 Hz. 

The A-Basis compressive properties (ref. 2) are shown in Table 11. The average of the three specimens 

tested is presented in Table 12 for both ambient and cryogenic tests. The individual test results are 

tabulated in Appendix B and the stress strain curves are included in Appendix D. 
13 

The ambient temperature compressive properties exceed the A-Basis properties for 2050 in the L and LT 

orientations. Through-thickness location dependent variations were noted in the L and LT orientations, 

with higher strengths and moduli at t/2 than at t/6 for all orientations. The 45° orientation showed no 

variation in strength or modulus with through-thickness location. 

As 2050 was originally intended for use at ambient temperatures, no cryogenic mechanical property data 

was available for a comparison with the presently reported data. In the present study, all of the specimen 

orientations exhibited an increase in strength and modulus as temperature was decreased from ambient 

temperature to -320°F. Variations in through-thickness compressive properties similar to those observed 

at ambient, were also observed at cryogenic temperatures.

For comparison, the typical compressive properties for 1.85 inch thick 2195-T8 (ref. 16) plate are shown 

in Table 13. The strength values for the 4 inch 2050-T84 plate are 17% lower than those of 2195-T8 at 

ambient temperature and 10% lower at cryogenic (-320°F) temperature. 

Table 11. A-Basis Compressive Properties of 4 inch thick 2050-T84 Plate (ref. 2) 

Orient. Fcy

(ksi)

Ec

(Msi)

L 66 11.3 

LT 64 11.3 

ST 59 11.3

Table 12. Average Compression Test Results for 4 inch thick 2050-T84 Plate

75°F -320°F

Orient. Plate 

Location

Fcy

(ksi)

Ec

(Msi)

Fcy

(ksi)

Ec

(Msi)

L t/2 74.9 11.2 86.4 12.3 

t/6 69.6 11.1 76.5 12.5

LT t/2 77.3 11.3 89.6 12.4 

t/6 71.3 11.2 82.0 12.4

45 t/2 70.5 11.0 81.3 12.2

t/6 69.6 11.0 81.9 12.3 
14 

Table 13. Typical Compression Properties of 1.85 inch thick 2195-T8 Plate (ref. 16) 

75°F -320°F 

Orient. Plate 

Location

Fcy

(ksi)

Ec

(Msi)

Fcy

(ksi)

Ec

(Msi)

L t/2 84.4 11.1 96.0 12.4

t/6 83.3 -- 92.8 --

LT t/2 85.5 -- -- --

t/6 81.2 -- 95.0 --

45 t/2 -- -- -- --

t/6 82.0 11.0 92.0 12.3 

6. Fracture Toughness 

Fracture toughness tests were carried out per ASTM E1820-09 (ref. 18) using compact tension, C(T), 

specimens with a width of 2.00 inches and thickness of 0.25 inch, illustrated in Figure 10. Specimens 

were extracted from the 4 inch 2050 plate at the t/6 location in the following orientations: L-T, T-L and 

L-S, as shown in Figure 11. Precracking was carried out at ambient temperature (75°F) in laboratory air 

for all specimens. Crack length during precracking was measured using compliance techniques. Fracture 

toughness tests were conducted at ambient temperature in laboratory air and cryogenic temperature 

(-320°F) immersed in liquid nitrogen. Crack length during fracture testing was measured using the 

potential drop method. Physical precrack and fracture lengths were measured in nine locations per ASTM 

E1820 and used in the determination of toughness. 

Results are presented in Table 14 for the average of three tests at the indicated temperatures and 

orientations. The individual test results are tabulated in Appendix B. All tests failed the validity 

requirements of ASTM E1820 due to deviations in crack front curvature. However, a comparison can still 

be made of the trends between the various orientations at ambient and cryogenic temperatures using 

conditional (KQJIC) fracture toughness values. At ambient temperature, fracture toughness was highest in 

the L-T orientation and lowest in the T-L orientation. At cryogenic temperature, fracture toughness was 

highest in the L-S orientation and lowest in the T-L orientation. An increase in fracture toughness from 

ambient to cryogenic temperature was observed for the T-L and L-S orientations, but not for the L-T 

orientation. There are limited published plane strain fracture data available for 2195, however the 

available data (ref. 4) show minimal increase or a decrease in fracture toughness, depending on 

orientation, for tests conducted at 75°F to -320°F, followed by a significant increase for tests conducted at 

-423°F. 
15 

Figure 10. Compact tension specimen (all dimensions in inches).

Figure 11. Compact tension specimen orientation with respect to plate.
16 

Table 14. Fracture Toughness of 4 inch thick 2050-T84 Plate at Ambient and Cryogenic 

Temperatures

75°F -320°F 

Orient. KQJIC

(ksi√in)

KQJIC

(ksi√in)

L-T 38.4 32.4

T-L 24.8 28.2 

L-S 33.3 44.4

7. Conclusions

Both the 2 inch and 4 inch plates exhibited elongated, lamellar microstructures typical of Al-Li rolled 

products. The through-thickness microstructures of both plates were uniform in regard to grain 

morphology, composition, hardness, and type and volume fraction of strengthening precipitates. Throughthickness variations in texture components observed in the 4 inch plate were rationalized as being due to 

strain gradients associated with rolling, which produces increased strain at t/2. The texture components 

correlated well with trends in yield strength. Stronger intensities of the deformation texture components 

explained the higher yield strength and greater anisotropy at the t/2 plate location in the 4 inch thick 2050-

T84 tested. Conversely, at the t/6 plate location weaker intensities of deformation texture components

were associated with lower yield strength but more isotropic properties observed. 

This preliminary examination of one lot of 2050 showed no apparent limitations to its potential use as a 

cryogenic tank alloy. Notwithstanding its yield and tensile strengths being lower than those of the current 

cryogenic tank alloy 2195, alloy 2050 exhibited similar trends in variations of strength properties versus 

temperature. The fracture toughness of 2050 showed a general increase as test temperature was decreased 

from ambient temperature to -320°F. This observation was also corroborated by the temperaturedependent increase observed in its strength and elongation during the tensile tests. In other words, for 

most sample orientations both strength and elongation increased with a decrease in temperature from 

75°F to -320°F. 

In the future, characterization of mechanical properties should be carried out at -423°F to verify the 

suitability of 2050 for use in liquid hydrogen tank structures. Additional fracture testing of 2050 should 

include surface flaw fracture specimens to better compare with existing data for 2195.

8. References

1. Lequeu, Ph; Smith, K. P.; and Danielou, A.: Aluminum-Copper-Lithium Alloy 2050 Developed 

for Medium to Thick Plate. J. Mat. Eng. and Perf., Vol. 19(6), August 2010, pp. 841-847. 

2. Federal Aviation Administration: Metallic Materials Properties Development and 

Standardization (MMPDS) MMPDS-05, Battelle Memorial Institute, Columbus, OH, April 2010. 

3. SAE Aerospace Material Specification 4413: Aluminum Alloy, Plate 3.5 Cu - 1.0Li - .40Mg - .35 

Mn - .45Ag - 0.12Zr (2050-T84) Solution Heat Treated, Stress Relieved, and Artificially Aged, 

SAE Aerospace, Oct. 2007. 
17 

4. Aerospace Structural Metals Handbook, edition 39, CINDAS Handbooks Operation West 

Lafayette, IN, March 2002. 

5. Lovejoy, A.E.; Chunchu, P.B.; Hilburger, M. W.. Ares-V Design Study: The Effects of Buckling 

Knockdown Factors, Internal Pressure, and Materials. NASA/TM-=2011-217061. February 2011. 

6. Metals Handbook, Ninth Edition, Volume 4, Heat Treating, American Society for Metals, 

November 1981, pp 688-695. 

7. J. Bunge: Z. Metallkunde. 56 (1965) No. 12, p. 872/874 

8. W.G. Fricke and M.A. Przystupa, “Texture”, in Aluminum Alloys - Contemporary Research and 

Applications, A.K. Vasudevan and R.D. Doherty (eds.), Treatise on Materials Science and 

Technology, Academic Press, San Diego, CA, vol.31, 1989, pp. 563-578. 

9. F.J. Humphreys and M. Hatherly, "Control of recrystallization", in Recrystallization and Related 

Annealing Phenomena, Second Edition, Elsevier Ltd., New York, NY, Ch.15, 2004, pp.469-505. 

10. Standard Test Method for Determining Specific Heat Capacity by Differential Scanning 

Calorimetry. ASTM Designation: E1269-05, Volume 14.02 of the 2010 Annual Book of ASTM 

Standards, 2010. 

11. NASA-STD-(I)-6001B - Flammability, Offgassing, And Compatibility Requirements And Test 

Procedures, April 2008.

12. NASA-STD-6016 - Standard Materials And Processes Requirements For Spacecraft, July 2008.

13. Standard Test Method for Determining Ignition Sensitivity of Materials to Mechanical Impact in 

Ambient Liquid Oxygen and Pressurized Liquid and Gaseous Oxygen Environments. ASTM 

Designation: G86-98, Volume 14.04 of the 2010 Annual Book of ASTM Standards, 2010. 

14. MAPTIS, https://maptis.ndc.nasa.gov/cgi-42/ctcore.exe, Accessed March 30, 2011. 

15. Standard Test Methods for Tension Testing of Metallic Materials. ASTM Designation E8-09, 

Volume 03.01 of the 2010 Annual Book of ASTM Standards, 2010. 

16. Reinmuller, R. E., Al-Li Materials Database Service Order 89818, Lockheed Martin Manned 

Space Systems, New Orleans, LA, Dec. 1996.

17. Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature. 

ASTM Designation: E9-09 Volume 03.01 of the 2010 Annual Book of ASTM Standards, 2010. 

18. Standard Test Method for Measurement of Fracture Toughness. ASTM Designation: E1820-06 

Volume 03.01 of the 2010 Annual Book of ASTM Standards, 2010. 
18 

Appendix A: Mill Certifications of 2050 Plate Used in this Study 
19 
20 
21 
22 

Appendix B: Individual Tensile, Compression and Fracture Toughness Test Data 

for 4 inch thick 2050-T84 Plate

Table B1. 2050-T84 Ambient Temperature (75°F) Tensile Results

Specimen # Orientation

Through 

Thickness 

Location

Fty (ksi) Ftu (ksi) E (Msi) eT (%)

1 L t/6 70.6 73.9 10.8 13.81

2 L t/6 70.5 73.9 10.8 13.73

3 L t/6 70.7 74.0 10.8 13.87

Average 70.6 73.9 10.8 13.80

1 L t/2 74.8 79.2 10.9 6.69*

2 L t/2 74.8 79.3 10.9 8.53

3 L t/2 74.5 79.1 10.9 9.07

Average 74.7 79.2 10.9 8.80

1 LT t/6 68.8 75.6 10.9 7.04*

2 LT t/6 68.9 75.7 10.9 11.51

3 LT t/6 70.6 75.8 10.8 11.03

Average 69.4 75.7 10.9 11.27

1 LT t/2 67.8 74.8 11.0 6.98*

2 LT t/2 67.9 74.7 11.0 8.83

3 LT t/2 68.3 74.9 11.0 8.11

Average 68.0 74.8 11.0 8.47

1 ST t/2 64.3 73.3 10.7 4.72

2 ST t/2 64.3 73.2 10.7 4.68

3 ST t/2 64.1 73.5 10.7 4.98

Average 64.2 73.3 10.7 4.79

1 L45ST t/2 63.7 68.7 10.9 2.36

2 L45ST t/2 62.8 67.8 10.9 2.60

3 L45ST t/2 62.8 67.8 10.9 2.60

Average 63.1 68.1 10.9 2.52

1 45 t/6 65.6 72.9 10.7 11.66

2 45 t/6 65.4 72.9 10.7 12.23

3 45 t/6 65.2 72.6 10.7 12.11

Average 65.4 72.8 10.7 12.00

1 45 t/2 65.9 72.7 10.7 9.63

2 45 t/2 65.6 72.4 10.7 9.71

4 45 t/2 65.4 72.3 10.7 10.31

Average 65.6 72.4 10.7 9.88

*Specimen broke outside extensometer knife edge, not included in average elongation 
23 

Table B2. 2050-T84 Cryogenic Temperature (-320°F) Tensile Results

Specimen # Orientation

Through 

Thickness 

Location

Fty (ksi) Ftu (ksi) E (Msi) eT (%)

4 L t/6 81.4 88.5 12.0 14.98*

5 L t/6 81.7 88.8 12.0 14.98*

6 L t/6 81.5 88.8 11.7 16.70**

7 L t/6 81.4 88.9 11.8 17.10**

Average 81.5 88.8 11.9 16.90

4 L t/2 — 95.9 12.1 —***

5 L t/2 86.1 95.8 12.1 11.05

6 L t/2 85.7 95.5 12.3 10.41

Average 85.9 95.7 12.2 10.73

4 LT t/6 79.4 91.5 12.1 12.00

5 LT t/6 79.5 91.6 11.9 12.25

6 LT t/6 80.6 91.6 12.1 12.33

Average 79.9 91.6 12.0 12.29

4 LT t/2 79.1 91.7 12.3 8.39

5 LT t/2 78.7 91.4 12.2 8.85

6 LT t/2 78.9 91.2 12.2 6.75

Average 78.9 91.4 12.2 7.80

4 ST t/2 73.1 87.6 11.9 5.45

5 ST t/2 73.0 87.0 11.9 4.84***

6 ST t/2 73.1 87.4 11.9 5.23

Average 73.1 87.3 11.9 5.34

4 L45ST t/2 72.9 81.4 12.0 3.48

5 L45ST t/2 71.8 80.7 11.9 4.08

6 L45ST t/2 76.1 84.8 11.9 3.19

Average 73.6 82.3 11.9 3.58

4 45 t/6 74.5 86.7 11.6 14.63**

5 45 t/6 74.5 86.8 11.5 14.55**

6 45 t/6 74.6 87.0 11.8 14.65**

Average 74.5 86.8 11.6 14.61

5 45 t/2 74.7 87.0 11.7 11.06

6 45 t/2 73.9 86.0 11.8 11.48

7 45 t/2 74.0 86.2 11.8 11.10

Average 74.2 86.4 11.8 11.21

*Extensometer off scale, not included in average elongation; **Used 0.9 inch gage length extensometer; 

***Extensometer slipped, not included in average elongation 
24 

Table B3. 2050-T84 Ambient Temperature (75°F) Compression Results

Specimen # Orientation

Through 

Thickness 

Location 

Fcy (ksi) Ec (Msi)

1 L t/2 74.6 11.1

2 L t/2 74.6 11.1

3 L t/2 75.3 11.2

Average 74.9 11.2

1 L t/6 69.3 11.1

3 L t/6 69.5 11.1

4 L t/6 69.9 11.1

Average 69.6 11.1

1 LT t/2 77.4 11.3

2 LT t/2 77.3 11.3

3 LT t/2 77.3 11.3

Average 77.3 11.3

1 LT t/6 71.4 11.2

2 LT t/6 71.6 11.2

3 LT t/6 71.0 11.2

Average 71.3 11.2

1 45 t/2 70.2 11.0

2 45 t/2 70.1 11.0

3 45 t/2 71.1 11.0

Average 70.5 11.0

1 45 t/6 69.6 11.0

2 45 t/6 69.9 11.0

3 45 t/6 69.2 11.0

Average 69.6 11.0
25 

Table B4. 2050-T84 Cryogenic Temperature (-320°F) Compression Results

Specimen # Orientation

Through 

Thickness 

Location 

Fcy (ksi) Ec (Msi)

4 L t/2 86.7 12.3

5 L t/2 86.3 12.3

6 L t/2 86.2 12.3

Average 86.4 12.3

5 L t/6 75.5 12.4

6 L t/6 78.7 12.5

2 L t/6 75.2 12.7

Average 76.5 12.5

4 LT t/2 90.1 12.2

5 LT t/2 89.8 12.5

6 LT t/2 88.8 12.5

Average 89.6 12.4

4 LT t/6 82.1 12.4

5 LT t/6 81.7 12.3

6 LT t/6 82.1 12.4

Average 82.0 12.4

4 45 t/2 80.4 12.1

5 45 t/2 81.1 12.2

6 45 t/2 82.5 12.2

Average 81.3 12.2

4 45 t/6 86.8 12.3

5 45 t/6 79.7 12.2

6 45 t/6 79.3 12.3

Average 81.9 12.3
26 

Table B5. 2050-T84 Ambient Temperature (75°F) Fracture Toughness Results

Specimen # Orientation

Through 

Thickness 

Location 

KQJIC

(ksi√in)

4 L-T t/6 37.6

5 L-T t/6 39.1

Average 38.4

1 T-L t/6 22.4

2 T-L t/6 26.3

4 T-L t/6 25.7

Average 24.8

1 L-S t/6 38.7

2 L-S t/6 36.3

3 L-S t/6 24.8

Average 33.3

Table B6. 2050-T84 Cryogenic Temperature (-320°F) Fracture Toughness Results

Specimen # Orientation

Through 

Thickness 

Location 

KQJIC

(ksi√in)

6 L-T t/6 34.1

7 L-T t/6 34.4

9 L-T t/6 28.8

Average 32.4

5 T-L t/6 27.2

6 T-L t/6 28.0

8 T-L t/6 29.5

Average 28.2

4 L-S t/6 43.7

5 L-S t/6 45.3

6 L-S t/6 44.1

Average 44.4
27 

Appendix C: Individual Stress-Strain Curves for Tensile Tests on 4 inch thick 

2050-T84 Plate

Figure C1. Tensile data for 2050-T84, L orientation, t/6, specimen 1, tested at 75oF. 
28 

Figure C2. Tensile data for 2050-T84, L orientation, t/6, specimen 2, tested at 75oF.

Figure C3. Tensile data for 2050-T84, L orientation, t/6, specimen 3, tested at 75oF.
29 

Figure C4. Tensile data for 2050-T84, L orientation, t/2, specimen 1, tested at 75oF.

Figure C5. Tensile data for 2050-T84, L orientation, t/2, specimen 2, tested at 75oF.
30 

Figure C6. Tensile data for 2050-T84, L orientation, t/2, specimen 3, tested at 75oF.

Figure C7. Tensile data for 2050-T84, LT orientation, t/6, specimen 1, tested at 75oF.
31 

Figure C8. Tensile data for 2050-T84, LT orientation, t/6, specimen 2, tested at 75oF.

Figure C9. Tensile data for 2050-T84, LT orientation, t/6, specimen 3, tested at 75oF.
32 

Figure C10. Tensile data for 2050-T84, LT orientation, t/2, specimen 1, tested at 75oF.

Figure C11. Tensile data for 2050-T84, LT orientation, t/2, specimen 2, tested at 75oF.
33 

Figure C12. Tensile data for 2050-T84, LT orientation, t/2, specimen 3, tested at 75oF.

Figure C13. Tensile data for 2050-T84, ST orientation, t/2, specimen 1, tested at 75oF.
34 

Figure C14. Tensile data for 2050-T84, ST orientation, t/2, specimen 2, tested at 75oF.

Figure C15. Tensile data for 2050-T84, ST orientation, t/2, specimen 3, tested at 75oF.
35 

Figure C16. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 1, tested at 75oF. 

Figure C17. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 2, tested at 75oF. 
36 

Figure C18. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 3, tested at 75oF. 

Figure C19. Tensile data for 2050-T84, 45o orientation, t/6, specimen 1, tested at 75oF.
37 

Figure C20. Tensile data for 2050-T84, 45o orientation, t/6, specimen 2, tested at 75oF.

Figure C21. Tensile data for 2050-T84, 45o orientation, t/6, specimen 3, tested at 75oF. 
38 

Figure C22. Tensile data for 2050-T84, 45o orientation, t/2, specimen 1, tested at 75oF.

Figure C23. Tensile data for 2050-T84, 45o orientation, t/2, specimen 2, tested at 75oF.
39 

Figure C24. Tensile data for 2050-T84, 45o orientation, t/2, specimen 3, tested at 75oF.

Figure C25. Tensile data for 2050-T84, L orientation, t/6, specimen 4, tested at -320oF. 
40 

Figure C26. Tensile data for 2050-T84, L orientation, t/6, specimen 5, tested at -320oF. 

Figure C27. Tensile data for 2050-T84, L orientation, t/6, specimen 6, tested at -320oF. 
41 

Figure C28. Tensile data for 2050-T84, L orientation, t/6, specimen 7, tested at -320oF. 

Figure C29. Tensile data for 2050-T84, L orientation, t/2, specimen 4, tested at -320oF. 
42 

Figure C30. Tensile data for 2050-T84, L orientation, t/2, specimen 5, tested at -320oF. 

Figure C31. Tensile data for 2050-T84, L orientation, t/2, specimen 6, tested at -320oF. 
43 

Figure C32. Tensile data for 2050-T84, LT orientation, t/6, specimen 4, tested at -320oF. 

Figure C33. Tensile data for 2050-T84, LT orientation, t/6, specimen 5, tested at -320oF. 
44 

Figure C34. Tensile data for 2050-T84, LT orientation, t/6, specimen 6, tested at -320oF. 

Figure C35. Tensile data for 2050-T84, LT orientation, t/2, specimen 4, tested at -320oF. 
45 

Figure C36. Tensile data for 2050-T84, LT orientation, t/2, specimen 5, tested at -320oF. 

Figure C37. Tensile data for 2050-T84, LT orientation, t/2, specimen 6, tested at -320oF. 
46 

Figure C38. Tensile data for 2050-T84, ST orientation, t/2, specimen 4, tested at -320oF. 

Figure C39. Tensile data for 2050-T84, ST orientation, t/2, specimen 5, tested at -320oF. 
47 

Figure C40. Tensile data for 2050-T84, ST orientation, t/2, specimen 6, tested at -320oF. 

Figure C41. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 4, tested at -320oF. 
48 

Figure C42. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 5, tested at -320oF. 

Figure C43. Tensile data for 2050-T84, L45ST orientation, t/2, specimen 6, tested at -320oF. 
49 

Figure C44. Tensile data for 2050-T84, 45o orientation, t/6, specimen 4, tested at -320oF. 

Figure C45. Tensile data for 2050-T84, 45o orientation, t/6, specimen 5, tested at -320oF. 
50 

Figure C46. Tensile data for 2050-T84, 45o orientation, t/6, specimen 6, tested at -320oF. 

Figure C47. Tensile data for 2050-T84, 45o orientation, t/2, specimen 5, tested at -320oF. 
51 

Figure C48. Tensile data for 2050-T84, 45o orientation, t/2, specimen 6, tested at -320oF. 

Figure C49. Tensile data for 2050-T84, 45o orientation, t/2, specimen 7, tested at -320oF. 
52 

Appendix D: Individual Stress-Strain Curves for Compression Tests on 4 inch 

thick 2050-T84 Plate

Absolute value of stress and strain plotted for all tests.

Figure D1. Compression data for 2050-T84, L orientation, t/2, specimen 1, tested at 75oF. 
53 

Figure D2. Compression data for 2050-T84, L orientation, t/2, specimen 2, tested at 75oF. 

Figure D3. Compression data for 2050-T84, L orientation, t/2, specimen 3, tested at 75oF. 
54 

Figure D4. Compression data for 2050-T84, L orientation, t/6, specimen 1, tested at 75oF. 

Figure D5. Compression data for 2050-T84, L orientation, t/6, specimen 3, tested at 75oF. 
55 

Figure D6. Compression data for 2050-T84, L orientation, t/6, specimen 4, tested at 75oF. 

Figure D7. Compression data for 2050-T84, LT orientation, t/2, specimen 1, tested at 75oF. 
56 

Figure D8. Compression data for 2050-T84, LT orientation, t/2, specimen 2, tested at 75oF. 

Figure D9. Compression data for 2050-T84, LT orientation, t/2, specimen 3, tested at 75oF. 
57 

Figure D10. Compression data for 2050-T84, LT orientation, t/6, specimen 1, tested at 75oF. 

Figure D11. Compression data for 2050-T84, LT orientation, t/6, specimen 2, tested at 75oF. 
58 

Figure D12. Compression data for 2050-T84, LT orientation, t/6, specimen 3, tested at 75oF. 

Figure D13. Compression data for 2050-T84, 45o orientation, t/2, specimen 1, tested at 75oF. 
59 

Figure D14. Compression data for 2050-T84, 45o orientation, t/2, specimen 2, tested at 75oF. 

Figure D15. Compression data for 2050-T84, 45o orientation, t/2, specimen 3, tested at 75oF. 
60 

Figure D16. Compression data for 2050-T84, 45o orientation, t/6, specimen 1, tested at 75oF. 

Figure D17. Compression data for 2050-T84, 45o orientation, t/6, specimen 2, tested at 75oF. 
61 

Figure D18. Compression data for 2050-T84, 45o orientation, t/6, specimen 3, tested at 75oF. 

Figure D19. Compression data for 2050-T84, L orientation, t/2, specimen 4, tested at -320oF. 
62 

Figure D20. Compression data for 2050-T84, L orientation, t/2, specimen 5, tested at -320oF. 

Figure D21. Compression data for 2050-T84, L orientation, t/2, specimen 6, tested at -320oF. 
63 

Figure D22. Compression data for 2050-T84, L orientation, t/6, specimen 2, tested at -320oF. 

Figure D23. Compression data for 2050-T84, L orientation, t/6, specimen 5, tested at -320oF. 
64 

Figure D24. Compression data for 2050-T84, L orientation, t/6, specimen 6, tested at -320oF. 

Figure D25. Compression data for 2050-T84, LT orientation, t/2, specimen 4, tested at -320oF.
65 

Figure D26. Compression data for 2050-T84, LT orientation, t/2, specimen 5, tested at -320oF.

Figure D27. Compression data for 2050-T84, LT orientation, t/2, specimen 6, tested at -320oF.
66 

Figure D28. Compression data for 2050-T84, LT orientation, t/6, specimen 4, tested at -320oF.

Figure D29. Compression data for 2050-T84, LT orientation, t/6, specimen 5, tested at -320oF.
67 

Figure D30. Compression data for 2050-T84, LT orientation, t/6, specimen 6, tested at -320oF.

Figure D31. Compression data for 2050-T84, 45o orientation, t/2, specimen 4, tested at -320oF.
68 

Figure D32 Compression data for 2050-T84, 45o orientation, t/2, specimen 5, tested at -320oF.

Figure D33. Compression data for 2050-T84, 45o orientation, t/2, specimen 6, tested at -320oF.
69 

Figure D34. Compression data for 2050-T84, 45o orientation, t/6, specimen 4, tested at -320oF.

Figure D35. Compression data for 2050-T84, 45o orientation, t/6, specimen 5, tested at -320oF.
70 

Figure D36. Compression data for 2050-T84, 45o orientation, t/6, specimen 6, tested at -320oF.
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