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chapter_3aluminum

MIL-HDBK-5H

1 December 1998

This chapter contains the engineering properties and related characteristics of wrought and cast aluminum alloys used in aircraft and missile structural applications.

General comments on engineering properties and the considerations relating to alloy selection are presented in Section 3.1. Mechanical and physical property data and characteristics pertinent to specific alloy groups or individual alloys are reported in Sections 3.2 through 3.10. Element properties are pre-sented in Section 3.11.

Aluminum is a lightweight, corrosion-resistant structural material that can be strengthened through alloying and, dependent upon composition, further strengthened by heat treatment and/or cold working [Reference 3.1(a)]. Among its advantages for specific applications are: low density, high strength-to-weight ratio, good corrosion resistance, ease of fabrication and diversity of form.

Wrought and cast aluminum and aluminum alloys are identified by a four-digit numerical designation, the first digit of which indicates the alloy group as shown in Table 3.1. For structural wrought aluminum alloys the last two digits identify the aluminum alloy. The second digit indicates modifications of the original alloy or impurity limits. For cast aluminum and aluminum alloys the second and third digits identify the aluminum alloy or indicate the minimum aluminum percentage. The last digit, which is to the right of the decimal point, indicates the product form: XXX.0 indicates castings, and XXX.1 and XXX.2 indicate ingot.

Table 3.1. Basic Designation for Wrought and Cast Aluminum Alloys

[Reference 3.1(b)]

— The layout of this chapter is in accordance with this four-digit number system for both wrought and cast alloys [Reference 3.1(b)]. Table 3.1.1 is the aluminum alloy index that illustrates both the general section layout as well as details of those specific aluminum alloys presently contained in this chapter. The wrought alloys are in Sections 3.2 through 3.7; whereas the cast alloys are in Sections 3.8 and 3.9.

— The properties of the aluminum alloys are determined by the alloy content and method of fabrication. Some alloys are strengthened principally by cold work, while others are strengthened principally by solution heat treatment and precipitation hardening [Reference 3.1(a)]. The temper designations, shown in Table 3.1.2 (which is based on Reference 3.1.2), are indicative of the type of strengthening mechanism employed.

Among the properties presented herein, some, such as the room-temperature, tensile, compressive,

shear and bearing properties, are either specified minimum properties or derived minimum properties related directly to the specified minimum properties. They may be directly useful in design. Data on the effect of temperature on properties are presented so that percentages may be applied directly to the room-temperature minimum properties. Other properties, such as the stress-strain curve, fatigue and fracture toughness data, and modulus of elasticity values, are presented as average or typical values, which may be used in assessing the usefulness of the material for certain applications. Comments on the effect of temperature on properties are given in Sections 3.1.2.1.7 and 3.1.2.1.8; comments on the corrosion resis-tance are given in Section 3.1.2.3; and comments on the effects of manufacturing practices on these proper-ties are given in Section 3.1.3.

3.1.2 MATERIAL PROPERTIES 3.1.1 ALUMINUM ALLOY INDEX

Temper Designation System ab

The temper designation system is used for all forms of wrought and cast aluminum and aluminum alloys except ingot. It is based on the sequences of basic treatments used to produce the various tem-pers. The temper designation follows the alloy designation, the two being separated by a hyphen. Basic temper designations consist of letters. Sub-divisions of the basic tempers, where required, are indicated by one or more digits following the letter. These designate specific sequences of basic treat-ments, but only operations recognized as signifi-cantly influencing the characteristics of the product are indicated. Should some other variation of the same sequence of basic operations be applied to the same alloy, resulting in different characteristics, then additional digits are added to the designation.

Basic Temper Designations

F as fabricated. Applies to the products of shap-

ing processes in which no special control over thermal conditions or strain-hardening is employed. For wrought products, there are no mechanical property limits.

O annealed. Applies to wrought products which are annealed to obtain the lowest strength temper, and to cast products which are annealed to improve ductility and dimensional stability. The O may be followed by a digit other than zero.

H strain-hardened (wrought products only).

Applies to products which have their strength increased by strain-hardening, with or without supplementary thermal treatments to produce some reduction in strength. The H is always followed by two or more digits.

W solution heat-treated. An unstable temper applicable only to alloys which spontaneously age at room temperature after solution heat-treatment. This designation is specific only when

the period of natural aging is indicated: for example, W ? hr.

T thermally treated to produce stable tempers other than F, O, or H. Applies to products which are thermally treated, with or without supplementary strain-hardening, to produce stable tempers. The T is always followed by one or more digits.

Subdivisions of H Temper: Strain-hardened. The first digit following H indicates the specific combination of basic operations, as follows:

H1strain-hardened only. Applies to products which are strain-hardened to obtain the desired strength without supplementary thermal treat-ment. The number following this designation indicates the degree of strain-hardening.

H2strain-hardened and partially annealed.

Applies to products which are strain-hardened more than the desired final amount and then reduced in strength to the desired level by partial annealing. For alloys that age-soften at room temperature, the H2 tempers have the same minimum ultimate tensile strength as the corresponding H3 tempers. For other alloys, the H2 tempers have the same minimum ultimate tensile strength as the corresponding H1 tempers and slightly higher elongation. The number following this designation indicates the degree of strain-hardening remaining after the product has been partially annealed.

H3strain-hardened and stabilized. Applies to products which are strain-hardened and whose mechanical properties are stabilized either by a low temperature thermal treatment or as a result

a From reference 3.1.2.

b Temper designations conforming to this standard for wrought aluminum and wrought aluminum alloys, and aluminum alloy

castings may be registered with the Aluminum Association provided: (1) the temper is used or is available for use by more than one user, (2) mechanical property limits are registered, (3) characteristics of the temper are significantly different from those of all other tempers which have the same sequence of basic treatments and for which designations already have been assigned for the same alloy and product, and (4) the following are also registered if characteristics other than mechanical properties are considered significant: (a) test methods and limits for the characteristics or (b) the specific practices used to produce the temper. Table 3.1.2. Temper Designation System for Aluminum Alloys

of heat introduced during fabrication.

Stabilization usually improves ductility. This designation is applicable only to those alloys which, unless stabilized, gradually age-soften at room temperature. The number following this designation indicates the degree of strain-hardening remaining after the stabilization treatment.

The digit following the designations H1, H2, and H3 indicates the degree of strain hardening. Nu-meral 8 has been assigned to indicate tempers having an ultimate tensile strength equivalent to that achieved by a cold reduction (temperature during reduction not to exceed 120 F) of approximately 75 percent following a full anneal. Tempers between O (annealed) and 8 are designated by numerals 1 through 7. Material having an ultimate tensile strength about midway between that of the O temper and that of the 8 temper is designated by the numeral 4; about midway between the O and 4 tempers by the numeral 2; and about midway between 4 and 8 tempers by the numeral 6. Numeral 9 designates tempers whose minimum ultimate tensile strength exceeds that of the 8 temper by 2.0 ksi or more. For two-digit H tempers whose second digit is odd, the standard limits for ultimate tensile strength are exactly midway between those of the adjacent two digit H tempers whose second digits are even. NOTE: For alloys which cannot be cold reduced an amount sufficient to establish an ultimate tensile strength applicable to the 8 temper (75 percent cold reduction after full anneal), the 6 temper tensile strength may be established by a cold reduction of approximately 55 percent following a full anneal, or the 4 temper tensile strength may be established by a cold reduction of approximately 35 percent after a full anneal.

The third digit c, when used, indicates a variation of a two-digit temper. It is used when the degree of control of temper or the mechanical properties or both differ from, but are close to, that (or those) for the two-digit H temper designation to which it is added, or when some other characteristic is significantly affected.

NOTE: The minimum ultimate tensile strength of a three-digit H temper must be at least as close to that of the corresponding two-digit H temper as it is to the adjacent two-digit H tempers. Products of the H temper whose mechanical properties are below H_1 shall be variations of H_1.

Three-digit H Tempers

H_11Applies to products which incur sufficient strain hardening after the final anneal that

they fail to qualify as annealed but not so

much or so consistent an amount of strain

hardening that they qualify as H_1.

H112Applies to products which may acquire some temper from working at an elevated

temperature and for which there are me-

chanical property limits.

Subdivisions of T Temper:

Thermally Treated

Numerals 1 through 10 following the T indicate specific sequences of basic treatments, as follows.d T1cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition. Applies to products which are not cold worked after cooling from an elevated temperature shaping process, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.

T2cooled from an elevated temperature shaping process, cold worked and naturally aged to a substantially stable condition. Applies to products which are cold worked to improve strength after cooling from an elevated temper-ature shaping process, or in which the effect of

c Numerals 1 through 9 may be arbitrarily assigne

d as th

e third digit and registered with The Aluminum Association for an alloy

and product to indicate a variation of a two-digit H temper (see footnote b).

d A period of natural aging at room temperatur

e may occur between or after the operations listed for the T tempers. Control o

f this

period is exercised when it is metallurgically important.

Table 3.1.2. Temper Designation System for Aluminum Alloys - Continued

cold work in flattening or straightening is recognized in mechanical property limits.

T3solution heat-treated e, cold worked, and natu-rally aged to a substantially stable condition.

Applies to products which are cold worked to improve strength after solution heat-treatment, or in which the effect of cold work in flattening or straightening is recognized in mechanical property limits.

T4solution heat-treated e and naturally aged to a substantially stable condition. Applies to products which are not cold worked after solu-tion heat-treatment, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.

T5cooled from an elevated temperature shaping process and artificially aged. Applies to products which are not cold worked after cooling from an elevated temperature shaping process, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.

T6solution heat-treated e and artificially aged.

Applies to products which are not cold worked after solution heat-treatment or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.

T7solution heat-treated e and overaged/ stabilized. Applies to wrought products that are artificially aged after solution heat-treatment to carry them beyond a point of maximum strength to provide control of some significant characteristic. Applies to cast products that are

artificially aged after solution heat-treatment to provide dimensional and strength stability.

T8solution heat-treated e, cold worked, and artificially aged. Applies to products which are cold worked to improve strength, or in which the effect of cold work in flattening or straightening is recognized in mechanical prop-erty limits.

T9solution heat-treated e, artificially aged, and cold worked. Applies to products which are cold worked to improve strength.

T10cooled from an elevated temperature shaping process, cold worked, and artificially aged.

Applies to products which are cold worked to improve strength, or in which the effect of cold work in flattening or straightening is recognized in mechanical property limits.

Additional digits f, the first of which shall not be zero, may be added to designations T1 through T10 to indicate a variation in treatment which signifi-cantly alters the product characteristics g that are or would be obtained using the basic treatment.

The following specific additional digits have been assigned for stress-relieved tempers of wrought products:

Stress Relieved by Stretching

T_51Applies to plate and rolled or cold-finished rod and bar when stretched the indicated

amounts after solution heat-treatment or

after cooling from an elevated temperature

shaping process. The products receive no

further straightening after stretching.

e Solution heat treatment is achieved by heating cast or wrought products to a suitable temperature, holding at that temperature

long enough to allow constituents to enter into solid solution and cooling rapidly enough to hold the constituents in solution.

Some 6000 series alloys attain the same specified mechanical properties whether furnace solution heat-treated or cooled from an elevated temperature shaping process at a rate rapid enough to hold constituents in solution. In such cases the temper

designations T3, T4, T6, T7, T8, and T9 are used to apply to either process and are appropriate designations.

f Additional digits may be arbitrarily assigned and registered with the Aluminum Association for an alloy and product to indicate a

variation of tempers T1 through T10 even though the temper representing the basic treatment has not been registered (see

footnote b). Variations in treatment which do not alter the characteristics of the product are considered alternate treatments for which additional digits are not assigned.

g For this purpose, characteristic is something other than mechanical properties. The test method and limit used to evaluate

material for this characteristic are specified at the time of the temper registration.

Table 3.1.2. Temper Designation System for Aluminum Alloys - Continued

Plate .... 1? to 3% permanent set.

Rolled or Cold-Finished

Rod and Bar .... 1 to 3% permanent set.

Die or Ring Forgings

and Rolled Rings .... 1 to 5% permanent set.

T_510Applies to extruded rod, bar, shapes and tube and to drawn tube when stretched the

indicated amounts after solution heat-

treatment or after cooling from an elevated

temperature shaping process. These prod-

ucts receive no further straightening after

stretching.

Extruded Rod, Bar, Shapes

and Tube .... 1 to 3% permanent set.

Drawn Tube .... ? to 3% permanent set.

T_511Applies to extruded rod, bar, shapes and tube and to drawn tube when stretched the

indicated amounts after solution heat-

treatment or after cooling from an elevated

temperature shaping process. These prod-

ucts may receive minor straightening after

stretching to comply with standard

tolerances.

Stress Relieved by Compressing

T_52Applies to products which are stress-relieved by compressing after solution heat-treatment

or cooling from an elevated temperature

shaping process to produce a set of 1 to 3

percent.

Stress Relieved by Combined

Stretching and Compressing

T_54Applies to die forgings which are stress relieved by restriking cold in the finish die. NOTE: The same digits (51, 52, 54) may be added to the designation W to indicate unstable solution heat-treated and stress-relieved treatment. The following temper designations have been assigned for wrought product test material heat-treated from annealed (O, O1, etc.) or F temper.h

T42Solution heat-treated from annealed or F temper and naturally aged to a substantially

stable condition.

T62Solution heat-treated from annealed or F temper and artificially aged.

Temper designations T42 and T62 may also be ap-plied to wrought products heat-treated from any temper by the user when such heat-treatment results in the mechanical properties applicable to these tempers.

Variations of O Temper: Annealed

A digit following the O, when used, indicates a product in the annealed condition have special char-acteristics. NOTE: As the O temper is not part of the strain-hardened (H) series, variations of O temper shall not apply to products which are strain-hardened after annealing and in which the effect of strain-hardening is recognized in the mechanical properties or other characteristics.

Assigned O Temper Variations

The following temper designation has been assigned for wrought products high temperature an-nealed to accentuate ultrasonic response and provide dimensional stability.

O1Thermally treated at approximately same time and temperature required for solution heat treatment and slow cooled to room tem-perature. Applicable to products which are to be machined prior to solution heat treatment by the user. Mechanical Property limits are not applicable.

Designation of Unregistered Tempers

The letter P has been assigned to denote H, T and O temper variations that are negotiated between manufacturer and purchaser. The letter P immediately follows the temper designation that

h When the user requires capability demonstrations from T-temper, the seller shall note “capability compliance” adjacent to the

specified ending tempers. Some examples are: “-T4 to -T6 Capability Compliance as for aging” or “-T351 to -T4 Capability Compliance as for resolution heat treating.”

Table 3.1.2. Temper Designation System for Aluminum Alloys - Continued

most nearly pertains. Specific examples where such designation may be applied include the following: The use of the temper is sufficiently limited so as to preclude its registration. (Negotiated H temper

variations were formerly indicated by the third digit zero.) The test conditions (sampling location, number of samples, test specimen configuration, etc.) are

different from those required for registration with the

Aluminum Association. The mechanical property limits are not established on the same basis as required for registration with the

Aluminum Association.

It should be recognized not all combinations of stress and environment have been investigated, and

it may be necessary to evaluate an alloy under the specific conditions involved for certain critical applications.

— The design strength properties at room temperature are listed at the beginning of the section covering the properties of an alloy.The effect of temperature on these properties is indicated in figures which follow the tables.

The A- and B-basis values for tensile properties for the direction associated with the specification

requirements are based upon a statistical analysis of production quality control data obtained from spe-cimens tested in accordance with procurement specification requirements. For sheet and plate of heat-treatable alloys, the specified minimum values are for the long-transverse (LT) direction, while for sheet and plate of nonheat treatable alloys and for rolled, drawn, or extruded products, the specified minimum values are for the longitudinal (L) direction. For forgings, the specified minimum values are stated for at least two directions. The design tensile properties in other directions and the compression, shear, and bearing properties are “derived” properties, based upon the relationships among the properties developed by tests of at least ten lots of material and applied to the appropriate established A, B, or S properties. All of these properties are representative of the regions from which production quality control specimens are taken, but may not be representative of the entire cross section of products appreciably thicker than the test specimen or products of complex cross sections.

Tensile and compressive strengths are given for the longitudinal, long-transverse, and short-transverse directions wherever data are available. Short-transverse strengths may be relatively low, and transverse properties should not be assumed to apply to the short-transverse direction unless so stated. In those instances where the direction in which the material will be used is not known, the lesser of the applicable longitudinal or transverse properties should be used.

Bearing strengths are given without reference to direction and may be assumed to be about the

same in all directions, with the exception of plate, die forging, and hand forging. A reduction factor is used for edgewise bearing load in thick bare and clad plate of 2000 and 7000 series alloys. The results of bearing tests on longitudinal and long-transverse specimens taken edgewise from plate, die forging, and hand forging have shown that the edgewise bearing strengths are substantially lower than those of specimens taken parallel to the surface. The bearing specimen orientations in thick plate are shown in Figure 3.1.2.1.1(a). For plate, bearing specimens are oriented so that the width of the specimen is parallel to the surfaces of the plate (flatwise); consequently, in cases where the stress condition approximates that of the longitudinal or long-transverse edgewise orientations, the reductions in design values shown in Table 3.1.2.1.1 should be made.

Table 3.1.2. Temper Designation System for Aluminum Alloys - Continued

3.1.2.1.1 Streng th (Tension, Compression, Shear, Bearing)

— Sustained stressing at elevated temperature sufficient

to result in appreciable amounts of creep deformation (e.g., more than 0.2 percent) may result in decreased strength and ductility. It may be necessary to evaluate an alloy under its stress-temperature environment for critical applications where sustained loading is anticipated (see Reference 3.1.2.1.4).

— Fatigue S/N curves are presented for those alloys for which sufficient data are available. Data for both smooth and notched specimens are presented. The data from which the curves were developed were insufficient to establish scatter bands and do not have the statistical reliability of the room-temperature mechanical properties; the values should be considered to be representative for the respective alloys.

The fatigue strengths of aluminum alloys, with both notched and unnotched specimens, are at least

as high or higher at subzero temperatures than at room temperature [References 3.1.2.1.5(a) through (c)].At elevated temperatures, the fatigue strengths are somewhat lower than at room temperature, the difference increasing with increase in temperature.

The data presented do not apply directly to the design of structures because they do not take into

account the effect of stress raisers such as reentrant corners, notches, holes, joints, rough surfaces, and other similar conditions which are present in fabricated parts. The localized high stresses induced in fabricated parts by such stress raisers are of much greater importance for repeated loading than they are for static loading and may reduce the fatigue life of fabricated parts far below that which would be predicted by comparing the smooth-specimen fatigue strength directly with the nominal calculated stresses for the parts in question. See References 3.1.2.1.5 (d) through (q) for information on how to use high-strength aluminum alloys, Reference 3.1.2.1.5(r) for details on the static and fatigue strengths of high-strength aluminum-alloy bolted joints, Reference 3.1.2.1.5(s) for single-rivet fatigue-test data, and Reference 1.4.9.3(b) for a general discussion of designing for fatigue. Fatigue-crack-growth data are presented in the various alloy sections.

— Typical values of plane-strain fracture toughness, K Ic , [Refer-ence 3.1.2.1.6(a)] for the high-strength aluminum alloy products are presented in Table 3.1.2.1.6. Mini-mum, average, and maximum values as well as coefficient of variation are presented for the alloys and tempers for which valid data are available [References 3.1.2.1.6(b) through (j)]. Although representative,these values do not have the statistical reliability of the room-temperature mechanical properties.

Graphic displays of the residual strength behavior of center-cracked tension panels are presented in

the various alloy sections. The points denote the experimental data from which the curve of fracture toughness was derived.

— In general, the strengths (including fatigue strengths) of

aluminum alloys increase with decrease in temperature below room temperature [References 3.1.2.1.7(a)and (b)]. The increase is greatest over the range from about -100 to -423°F (liquid hydrogen temperature);the strengths at -452°F (liquid helium temperature) are nearly the same as at -423°F [References 3.1.2.1.7(c) and (d)]. For most alloys, elongation and various indices of toughness remain nearly constant or increase with decrease in temperature, while for the 7000 series, modest reductions are observed [Refer-ences 3.1.2.1.7(d) and (e)]. None of the alloys exhibit a marked transition in fracture resistance over a nar-row range of temperature indicative of embrittlement.

3.1.2.1.4 Creep and Stress Rupture 3.1.2.1.5 Fatigue

3.1.2.1.6 Fracture Toughness 3.1.2.1.7 Cryogenic Temperatures

3-11

Supersedes page 3-11 of MIL-HDBK-5H

Table 3.1.2.1.6. Values of Room-Temperature Plane-Strain Fracture Toughness of Aluminum Alloys

Alloy/Temper b

Product Form Orien-tation c Product Thickness Range,inches

Number of Sources

Sample Size

Specimen Thickness Range,inches

K IC , ksi %&i n.

Max.Avg.Min.Coefficient of

Variation

Minimum Specification Value

2014-T6512014-T6512014-T6522014-T6522024-T3512024-T8512024-T8512024-T8512024-T8522024-T8522024-T8522124-T8512124-T8512124-T8512219-T8512219-T8512219-T8512219-T8512219-T85112219-T8522219-T8522219-T8522219-T872219-T877040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T74517040-T7451Plate Plate

Hand Forging Hand Forging Plate Plate Plate Plate Forging

Hand Forging Hand Forging Plate Plate Plate Plate Plate Plate Forging Extrusion Forging

Hand Forging Hand Forging Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate L-T T-L L-T T-L L-T L-S L-T T-L T-L L-T T-L L-T T-L S-L L-T T-L S-L S-L T-L S-L L-T T-L L-T T-L L-T T-L S-L L-T T-L S-L L-T T-L S-L L-T T-L S-L L-T T-L $0.5$0.5$0.5$0.8$1.01.4-3.0$0.50.4-4.02.0-7.0--------$0.80.6-6.0$0.5----$1.0$0.8----------------$1.5$1.5----3-43-43-44-54-54-55-65-65-66-76-76-77-87-8122224119342131064631122231111111111111112434151511111028020351749750948967108248519603228111116161417171717141621212118160.5-1.00.5-1.00.8-2.00.8-2.00.8-2.00.5-0.80.4-1.40.4-1.40.7-2.00.8-2.00.7-2.00.5-2.50.5-2.00.3-1.51.0-2.50.8-2.50.5-1.51.0-1.51.8-2.00.8-2.01.5-2.51.5-2.50.8-2.01.022222222222222

2523483043323225253822383227383726343435463034223931333427283428283729303329

2221312131252320192818292521332922252925382727223730313226263225273427293228

1918241827201518151914181916302020192320302225193428293126263025263025273026

8.46.521.814.416.517.810.18.815.518.414.410.49.79.87.210.19.612.112.312.19.78.49.33.95.22.84.22.01.52.22.73.52.75.92.84.03.22.7

242018

3126243025242923242722232622

a These values are for information only.

b Products that do not receive a mechanical stress-relieving process (e.g. -T73 & -T74 tempers) have the potential for induced residual stresses. As a result, care must be taken to prevent fracture toughness properties from bias resulting from residual stresses.

c Refer to Figure 1.4.12.3 for definition of symbols.

d Varies with thickness.

3-12

Supersedes page 3-12 of MIL-HDBK-5H

Table 3.1.2.1.6. Values of Room-Temperature Plane-Strain Fracture Toughness of Aluminum

Alloys a —Continued

Alloy/Temper b

Product Form Orien-tation c Product Thickness Range,inches

Number of Sources

Sample Size

Specimen Thickness Range,inches

K IC , ksi %&i n.

Max.Avg.Min.Coefficient

of Variation

Minimum Specification Value

7040-T74517040-T74517040-T74517040-T74517049-T737049-T737049-T737049-T737049-T737050-T73517050-T73517050-T73517050-T747050-T74517050-T74517050-T74517050-T74527050-T74527050-T74527050-T765117075-T6517075-T6517075-T6517075-T65107075-T65107075-T65107075-T65107075-T737075-T737075-T737075-T73517075-T73517075-T73517075-T735117075-T73511Plate Plate Plate Plate

Die Forging Die Forging Hand Forging Hand Forging Hand Forging Plate Plate Plate

Die Forging Plate Plate Plate

Hand Forging Hand Forging Hand Forging Extrusion Plate Plate Plate Extrusion Extrusion Forged Bar Forged Bar Die Forging Hand Forging Hand Forging Plate Plate Plate Extrusion Extrusion S-L L-T T-L S-L L-T S-L L-T T-L S-L L-T T-L S-L S-L L-T T-L S-L L-T T-L S-L L-T L-T T-L S-L L-T T-L L-T T-L T-L L-T T-L L-T T-L S-L T-L L-T

7-88-8.58-8.58-8.51.4$0.5$0.52.0-7.11.01.0-6.02.0-6.02.0-6.00.6-7.1----$1.0$1.03.5-5.53.5-7.53.5-7.5----$0.6$0.5----0.7-3.50.7-3.50.7-5.00.7-5.0$0.5----$1.0$1.0$0.5$0.51.0-7.0$0.9

1111332222113139611127521111122863131317131721462827243129301296974411131738991353726251313221014655620192822220.5-1.00.5-1.00.5-1.01.00.8-1.01.0-2.01.5-2.00.8-1.50.6-2.01.0-2.00.5-2.00.7-2.01.51.50.8-1.50.6-2.00.5-2.00.4-2.00.5-1.50.5-1.20.5-1.20.6-2.00.5-2.50.5-0.81.0-1.51.0-1.50.5-2.00.5-2.00.5-1.50.9-1.00.7-2.0

3134262734263728224335302739382834222140302722322835242539273647382243

2931242630223022193530282432282331211931262218272429212131233027222035

2628232527182318142825252125212126181627201814232124171829202521171931

4.64.6

5.02.17.49.712.112.514.211.38.54.68.811.715.6

6.38.06.7

7.57.87.6

8.910.47.88.011.68.2

9.98.89.08.220.132.53.79.4

23262222

d d d d d d

a These values are for information only.

c Refer to Figure 1.4.12.3 for definition of symbols.

3-13

Supersedes page 3-13 of MIL-HDBK-5H

Table 3.1.2.1.6. Values of Room-Temperature Plane-Strain Fracture Toughness of Aluminum

Alloys a —Continued

Alloy/Temper b

Product Form Orien-tation c Product Thickness Range,inches

Number of Sources

Sample Size

Specimen Thickness Range,inches

K IC , ksi %&i n.

Max.Avg.Min.Coefficient

of Variation

Minimum Specification Value

7075-T735117075-T735117075-T73527075-T73527075-T76517075-T76517075-T76517075-T76517075-T76517075-T765117075-T765117175-T6/T65117175-T6517175-T6517175-T65117175-T73517175-T73517175-T735117175-T735117175-T747175-T747175-T747175-T747175-T76517175-T76517175-T76517175-T76517175-T765117175-T765117475-T6517475-T6517475-T6517475-T73517475-T73517475-T73517475-T76517475-T7651Extrusion Extrusion Hand Forging Hand Forging Plate Plate Plate

Clad Plate Clad Plate Extrusion Extrusion Extrusion Plate Plate Extrusion Plate Plate Extrusion Extrusion Die Forging Die Forging Die Forging Hand Forging Clad Plate Clad Plate Plate Plate Extrusion Extrusion Plate Plate Plate Plate Plate Plate Plate Plate T-L S-L L-T T-L L-T T-L S-L L-T T-L L-T T-L T-L L-T T-L L-T L-T T-L L-T T-L L-T T-L S-L T-L L-T T-L L-T T-L L-T T-L L-T T-L S-L L-T T-L S-L L-T T-L

$0.7$0.5----$0.8$0.8$0.5$0.50.5-0.60.5-0.61.3-7.01.2------------------------$0.7$0.5$0.5$0.5$0.53.0-5.0----------------1.4-3.8$0.6----0.6-2.0$0.61.3-4.0$1.3$0.71.0-2.0$1.0

3323675224321122255324211112432187742351527208296283056114225171014303243431413411053501211484934143231511327410150.5-1.80.4-1.00.8-2.00.8-2.00.5-2.00.5-2.00.4-0.80.5-0.60.5-0.61.2-2.00.6-2.00.8-1.00.7-0.80.7-0.80.8-1.00.7-1.60.7-1.60.5-1.50.5-1.50.5-1.00.5-1.00.5-0.81.0-1.51.50.61.51.50.6-2.00.6-1.80.9-2.00.6-2.00.5-1.01.3-3.00.7-3.00.5-1.51.0-2.00.9-2.0

35223933432820302841362430263636304735383331293328322639314943366050364650

23203326292318252435232126223233273325302426263227322533223834284737304136

12173023222015222131201824202432252320222120243025312427203327203429253629

20.39.09.29.917.87.67.77.17.711.015.57.99.29.813.83.34.516.010.915.015.78.64.84.33.11.73.310.79.89.29.814.910.410.48.76.214.5

302227212125

3028d d 253330

a These values are for information only.

MIL-HDBK-5H, Change Notice 1

1 October 2001

The tensile and shear moduli of aluminum alloys also increase with decreasing temperature so that at -100, -320, and -423E F, they are approximately 5, 12, and 16 percent, respectively, above the room temperature values [Reference 3.1.2.1.7(f)].

3.1.2.1.8 Elevated Temperatures— In general, the strengths of aluminum alloys decrease and toughness increases with increase in temperature and with time at temperature above room temperature; the effect is generally greatest over the temperature range from 212 to 400E F. Exceptions to the general trends are tempers developed by solution heat treatment without subsequent aging, for which the initial elevated temperature exposure results in some age hardening and reduction in toughness; further time at temperature beyond that required to achieve peak hardness results in the aforementioned decrease in strength and increase in toughness [Reference 3.1.2.1.8].

3.1.2.2 Physical Properties— Where available from the literature, the average values of certain physical properties are included in the room-temperature tables for each alloy. These properties include density, ω, in lb/in.3; the specific heat, C, in Btu/(lb)(E F); the thermal conductivity, K, in Btu/[(hr)(ft2)(E F)/ft]; and the mean coefficient of thermal expansion, α, in in./in./ E F. Where more extensive data are available to show the effect of temperature on these physical properties, graphs of physical property as a function of temperature are presented for the applicable alloys.

3.1.2.3 Corrosion Resistance —

[see References 3.1.2.3.1(a) through

3.1.2.3.1 Resistance to Stress-Corrosion Cracking

(d)] — In-service stress-corrosion cracking failures can be caused by stresses produced from a wide variety of sources, including solution heat treatment, straightening, forming, fit-up, clamping, and sustained service loads. These stresses may be tensile or compressive, and the stresses due to Poisson effects should not be ignored because SCC failures can be caused by sustained shear stresses. Pin-hole flaws in some corrosion protection coatings may also be sufficient to allow SCC to occur. The high-strength heat treatable wrought aluminum alloys in certain tempers are susceptible to stress-corrosion cracking, depending upon product, section size, direction and magnitude of stress. These alloys include 2014, 2025, 2618, 7075, 7150, 7175, and 7475 in the T6-type tempers and 2014, 2024, 2124, and 2219 in the T3 and T4-type tempers. Other alloy-temper combinations, notably 2024, 2124, 2219, and 2519 in the T6- or T8-type tempers and 7010, 7049, 7050, 7075, 7149, 7175, and 7475 in the T73-type tempers, are decidedly more resistant and sustained tensile stresses of 50 to 75 percent of the minimum yield strength may be permitted without concern about stress corrosion cracking. The T74 and T76 tempers of 7010, 7075, 7475, 7049, 7149, and 7050 provide an intermediate degree of resistance to stress-corrosion cracking, i.e., superior to that of the T6 temper, but not as good as that of the T73 temper of 7075. To assist in the selection of materials, letter ratings indicating the relative resistance to stress-corrosion cracking of various mill product forms of the wrought 2000, 6000, and 7000 series heat-treated aluminum alloys are presented in Table 3.1.2.3.1(a). This table is based upon ASTM G 64 which contains more detailed information regarding this rating system and the procedure for determining the ratings. In addition, more quantitative information in the form of the maximum specified tension stresses at which test specimens will not fail when subjected to the alternate immersion stress-corrosion test described in ASTM G 47 are shown in Tables 3.1.2.3.1(b) through (e) for various heat-treated aluminum product forms, alloys, and tempers.

Where short times at elevated temperatures of 150 to 500E F may be encountered, the precipitation heat-treated tempers of 2024 and 2219 alloys are recommended over the naturally aged tempers.

Alloys 5083, 5086, and 5456 should not be used under high constant applied stress for continuous service at temperatures exceeding 150E F, because of the hazard of developing susceptibility to stress-corrosion cracking. In general, the H34 through H38 tempers of 5086, and the H32 through H38 tempers

Table 3.1.2.3.1(a). Resistance to Stress-Corrosion Ratings a for High-Strength Aluminum Alloy Products

Alloy and Temper b

Test

Direction c

Rolled

Plate

Rod and

Bar d

Extruded

Shapes Forging

2014-T6

2024-T3, T4 2024-T6

2024-T8

2124-T8

2219-T351X, T37 2219-T6

2219-T85XX, T87 6061-T6

7040-T7451 7049-T73

7049-T76

7050-T74

7050-T76

7075-T6

7075-T73

B e

A e

B e

Table 3.1.2.3.1(a). Resistance to Stress-Corrosion Ratings a for High-Strength Aluminum Alloy Products—Continued

Alloy and Temper b

Test

Direction c

Rolled

Plate

Rod and

Bar d

Extruded

Shapes Forging

7075-T74 7075-T76 7149-T73 7175-T74 7475-T6 7475-T73 7475-T76

B e

a Ratings were determined from stress corrosion tests performed on at least ten random lots for which test results showed 90%

conformance with 95% confidence when tested at the following stresses.

A -Equal to or greater than 75% of the specified minimum yield strength. A very high rating. SCC not anticipated in general

applications if the total sustained tensile stress* is less than 75% of the minimum specified yield stress for the alloy, heat treatment, product form, and orientation.

B -Equal to or greater than 50% of the specified minimum yield strength. A high rating. SC

C not anticipated if the total

sustained tensile stress* is less than 50% of the specified minimum yield stress.

C -Equal to or greater than 25% of the specified minimum yield stress or 14.5 ksi, whichever is higher. An intermediate

rating. SCC not anticipated if the total sustained tensile stress* is less than 25% of the specified minimum yield stress.

This rating is designated for the short transverse direction in improved products used primarily for high resistance to

exfoliation corrosion in relatively thin structures where applicable short transverse stresses are unlikely.

D -Fails to meet the criterion for the rating C. A low rating. SCC failures have occurred in service or would be anticipated if

there is any sustained tensile stress* in the designated test direction. This rating currently is designated only for the short transverse direction in certain materials.

NOTE -The above stress levels are not to be interpreted as “threshold” stresses, and are not recommended for design. Other documents, such as MIL-STD-1568, NAS SD-24, and MSFC-SPEC-522A, should be consulted for design

recommendations.

* The sum of all stresses, including those from service loads (applied), heat treatment, straightening, forming, etc.

MIL-HDBK-5H

1 December 1998

Table 3.1.2.3.1(a). Resistance to Stress-Corrosion Ratings TM for High Strength Aluminum Alloy Products - Continued

b The ratings apply to standard mill products in the types of tempers indicated, including stress-relieved tempers, and could be

invalidated in some cases by application of nonstandard thermal treatments of mechanical deformation at room temperature by the user.

c Test direction refers to orientation of the stressing direction relative to the directional grain structure typical of wrought materials,

which in the case of extrusions and forgings may not be predictable from the geometrical cross section of the product.

L Longitudinal: parallel to the direction of principal metal extension during manufacture of the product.

LT Long Transverse: perpendicular to direction of principal metal extension. In products whose grain structure clearly shows directionality (width to thickness ratio greater than two) it is that perpendicular direction parallel to the major grain dimension.

ST Short Transverse: perpendicular to direction of principal metal extension and parallel to minor dimension of grains in products with significant grain directionality.

d Sections with width-to-thickness ratio equal to or less than two for which ther

e is no distinction between LT and ST.

e Rating is one class lower for thicker sections: extrusion, 1 inch and over; plate and forgings, 1.5 inches and over.

f Ratings not established because the product is not offered commercially.

NOTE: This table is based upon ASTM G 64.

MIL-HDBK-5H, Change Notice 1

1 October 2001

Table 3.1.2.3.1(b). Maximum Specified Tension Stress at Which Test Specimens Will Not Fail in 3?% NaCl Alternate Immersion Test a for Various Stress Corrosion Resistant Aluminum Alloy Plate

Alloy and Temper

Test

Direction

Thickness,

inches

Stress,

ksi Referenced Specifications

2024-T851 2090-T81c 2124-T851

2124-T8151c

2219-T851 2219-T87

2519-T87

7010-T7351c

7010-T7451 7010-T7651 7049-T7351 7050-T7451 7050-T7651 7075-T7351

7075-T7651 Clad 7075-T7651 7150-T7751 7475-T7351 7475-T7651ST

1.001-4.000

4.001-6.000

0.750-1.500

1.500-1.999

2.000-4.000

4.001-6.000

1.500-3.000

3.001-5.000

5.001-

6.000

0.750-2.000

2.001-4.000

4.001-

5.000

5.001-

6.000

0.750-3.000

3.001-

4.000

4.001-

5.000

0.750-4.000

0.750-3.000

3.001-5.000

5.001-5.500

0.750-3.000

3.001-5.500

0.750-5.500

0.750-5.000

0.750-6.000

0.750-3.000

0.750-2.000

2.001-2.500

2.501-4.000

0.750-1.000

0.750-3.000

0.750-4.000

0.750-1.500

28b

27b

28b

27b

30b

29b

28b

34d

33d

32d

31d

38d

37d

36d

43d

41d

40d

39d

31b

42d

39d

36d

Company specification

AMS 4303

AMS 4101

AMS-QQ-A-0025/29, ASTM B 209, AMS 4101

AMS 4221

AMS-QQ-A-250/30

MIL-A-46192

AMS 4203

AMS 4205

AMS 4204

AMS 4200

AMS 4050

AMS 4201

AMS-QQ-A-250/12, AMS 4078, ASTM B 209

AMS-QQ-A-00250/24, ASTM B 209

AMS-QQ-A-00250/25, ASTM B 209

AMS 4252

AMS 4202

AMS 4089

a Most specifications reference ASTM G 47, which requires exposures of 10 days for 2XXX alloys and 20 days for 7XXX alloys in ST

test direction.

b 50% of specified minimum long transverse yield strength.

c Design values are not include

d in MIL-HDBK-5.

d 75% of specified minimum long transvers

e yield strength.

DO NOT USE STRESS VALUES FOR DESIGN

Table 3.1.2.3.1(c). Maximum Specified Tension Stress at Which Test Specimens Will Not Fail in 3?% NaCl Alternate Immersion Test a for Various Stress Corrosion Resistant Aluminum Alloy Rolled Bars, Rods, and Extrusions

Alloy and Temper Product

Form

Test

Direction

Thickness,

inches

Stress,

ksi Referenced Specifications

7075-T73-T7351

2219-T8511

7049-T73511

7049-T76511d

7050-T73511

7050-T74511

7050-T76511

7075-T73-T73510-T73511

7075-T76-T76510-T76511 7149-T73511d

7150-T77511

7175-T73511Rolled Bar

and Rod

Extrusion

0.750-3.000

0.750-2.999

3.000-5.000

0.750-5.000

0.750-1.499

1.500-

2.999

3.000-

4.999

3.000-

4.999

0.750-1.000

0.750-2.999

3.000-5.000

0.750-2.000

42b

41c

40c

45b

44b

42b

41b,e

41c

40c

AMS-QQ-A-225/9, AMS 4124, ASTM B211

AMS 4162, AMS 4163

AMS 4157

AMS 4159

AMS 4341

AMS 4342

AMS 4340

AMS-QQ-A-200/11, AMS 4166, AMS 4167, ASTM B

211

AMS-QQ-A-200/15, ASTM B 221

AMS 4543

AMS 4345

AMS 4344

a Most specifications reference ASTM G 47, which requires exposures of 10 days for 2XXX alloys and 20 days for 7XXX alloys in ST test direction.

b 75% of specified minimum longitudinal yield strength.

c 65% of specifie

d minimum longitudinal yield strength.

d Design values ar

e not included in MIL-HDBK-5.

e Over 20 square inches cross-sectional area.

DO NOT USE STRESS VALUES FOR DESIGN

Table 3.1.2.3.1(d). Maximum Specified Tension Stress at Which Test Specimens Will Not Fail in 3?% NaCl Alternate Immersion Test a for Various Stress Corrosion Resistant Aluminum Die Forgings

Alloy and Temper

Test

Direction

Thickness,

inches

Stress,

ksi Referenced Specifications

7049-T73 7050-T74 7050-T7452 7075-T73

7075-T7352 7075-T7354c 7075-T74c

7149-T73 7175-T74

7175-T7452c ST

0.750-2.000

2.001-5.000

0.750-6.000

0.750-4.000

0.750-3.000

3.001-

4.000

4.001-

5.000

5.001-

6.000

0.750-4.000

3.001-

4.000

0.750-3.000

3.001-

4.000

4.001-

5.000

5.001-

6.000

0.750-2.000

2.001-5.000

0.750-3.000

3.001-

4.000

4.001-

5.000

5.001-

6.000

0.750-3.000

46b

45b

42b

41b

39b

38b

42b

39b

31d

30d

29d

46b

45b

31d

30d

29d

QQ-A-367, AMS 4111, ASTM B 247

AMS 4107

AMS 4333

MIL-A-22771, QQ-A-367

AMS 4241, ASTM B 247

AMS 4141

MIL-A-22771, QQ-A-367, AMS 4147,

ASTM B 247

Company Specification

AMS 4131

AMS 4320

AMS 4149, ASTM B 247

AMS 4149

AMS 4179

a Most specifications Reference ASTM G 47, which requires 20 days of exposure for 7XXX alloys in ST test direction.

b 75% of specified minimum longitudinal yield strength.

c Design values are not include

d in MIL-HDBK-5.

d 50% of specified minimum longitudinal yield strength.

DO NOT USE STRESS VALUES FOR DESIGN