MMPDS-01 31 January 2003

CHAPTER 4 MAGNESIUM ALLOYS 4.1

GENERAL

This chapter contains the engineering properties and characteristics of wrought and cast magnesium alloys used in aircraft and missile applications. Magnesium is a lightweight structural metal that can be strengthened greatly by alloying, and in some cases by heat treatment or cold work or by both. 4.1.1 ALLOY INDEX — The magnesium alloys in this chapter are listed in alphanumeric sequence in each of two parts, the first one being wrought forms of magnesium and the second cast forms. These sections and the alloys covered under each are shown in Table 4.1.

Table 4.1. Magnesium Alloys Index

Section 4.2 4.2.1 4.2.2 4.2.3 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.3.6

Designation Magnesium-Wrought Alloys AZ31B AZ61A ZK60A Magnesium-Cast Alloys AM100A AZ91C/AZ91E AZ92A EZ33A QE22A ZE41A

4.1.2 MATERIAL PROPERTIES 4.1.2.1 Mechanical Properties — The mechanical properties are given either as design values or for information purposes. The tensile strength (Ftu), tensile yield strength (Fty), elongation (e), and sometimes the compressive yield strength (Fcy) are guaranteed by procurement specifications. The properties obtained reflect the location of sample, type of test specimen and method of testing required by the product specification. The remaining design values are “derived” values; that is, sufficient tests have been made to ascertain that if a given material meets the requirements of the product specification, the material will have the compression (Fcy), shear (Fsu) and bearing (Fbru and Fbry) strengths listed. 4.1.2.1.1 Tension Testing — Room-temperature tension tests are made according to ASTM E 8. The yield strength (Fty) is obtained by the “offset method” using an offset of 0.2 percent. The speed of testing for room-temperature tests has a small effect on the strength and elongation values obtained on most magnesium alloys. The rate of stressing generally specified to the yield strength is less than 100,000 psi per minute and the rate of straining from the yield strength to fracture is less than 0.5 in./in./min. It can be

4-1

MMPDS-01 31 January 2003 expected that the speed of testing used for room-temperature tension tests will approach the maximum permitted. Elevated-temperature tension tests are made according to ASTM E 21. The speed of testing has a considerable effect on the results obtained and no one standard rate of straining is given in ASTM E 21. The strain rates most commonly used on magnesium are 0.005 in./in./min. to the yield and 0.10 in./in./min. from yield to fracture [see References 4.1.2.1.1(a) to (d)]. 4.1.2.1.2 Compression Testing — Compression test methods used for magnesium are specified in ASTM E 9. The values given for the compressive yield strength (Fcy), are taken at an offset of 0.2 percent. References 4.1.2.1.2(a) and (b) provide information on test techniques. 4.1.2.1.3 Bearing Testing — Bearing tests of magnesium alloys are made according to ASTM E 238. The size of pin used has a significant effect on the values obtained, especially the bearing ultimate strength (Fbru). On tests made to obtain the data on magnesium alloys shown in this document, pin diameters of 0.187 and 0.250 inch were used. For pin diameters significantly larger than 0.250 inch lower values may be obtained. Additional information on bearing testing is given in References 4.1.2.1.3(a) and (b). Bearing values in the property tables are considered to be “dry pin” values in accordance with the discussion in Section 1.4.7.1. 4.1.2.1.4 Shear Testing — The shear strength values used in this document were obtained by the “double shear” method using a pin-type specimen, the “punch shear” method and the “tension shear” method as applicable. Just as tensile ultimate strength (Ftu) values vary with location and direction of sample in relation to the method of fabrication, the shear strength (Fsu) may be expected to reflect the effect of orientation, either as a function of the sampling or the maximum stresses imposed by the method of test. Information on shear testing is given in Reference 4.1.2.1.4. 4.1.2.1.5 Stress Raisers — The effect of notches, holes, and stress raisers on the static properties of magnesium alloys is described in References 4.1.2.1.5(a) through (c). Additional data on the strength properties of magnesium alloys are presented in References 4.1.2.1.5(d) through (h). 4.1.2.1.6 Creep — Some creep data on magnesium alloys are summarized in Reference 4.1.2.1.6. 4.1.2.1.7 Fatigue — Room-temperature axial load fatigue data for several magnesium alloys are presented in appropriate alloy sections. References 4.1.2.1.7(a) and (b) provide additional data on fatigue of magnesium alloys. 4.1.3 PHYSICAL PROPERTIES — Selected experimental data from the literature were used in determining values for physical properties. In other cases, enough information was available to calculate the constants. Estimated values of some of the remaining constants were also included. Estimated values are noted. 4.1.4 ENVIRONMENTAL CONSIDERATIONS — Corrosion protection must be considered for all magnesium applications. Protection can be provided by anodic films, chemical conversion coatings, paint systems, platings, or a combination of these methods. Proper drainage must be provided to prevent entrapment of water or other fluids. Dissimilar metal joints must be properly and completely insulated, including barrier strips and sealants. Strain-hardened or age-hardened alloys may be annealed or overaged by prolonged exposure to elevated temperatures, with a resulting decrease in strength. Maximum recommended temperatures for prolonged service are reported, where available, for specific alloys.

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MMPDS-01 31 January 2003 4.1.5 ALLOY AND TEMPER DESIGNATIONS — Standard ASTM nomenclature is used for the alloys listed. Temper designations are given in ASTM B 296. A summary of the temper designations is given in Table 4.1.5. Table 4.1.5. Temper Designation System for Magnesium Alloysa Basis of Codification The designations for temper are used for all forms of magnesium and magnesium alloy products except ingots and are based on the sequence of basic treatments used to produce the various tempers. The temper designation follows the alloy designation, the two being separated by a dash. Basic temper designations consist of letters. Subdivisions of the basic tempers, where required, are indicated by a digit or digits following the letter. These designate specific sequences of basic treatments, but only operations recognized as significantly 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.

NOTE—In material specifications containing reference to two or more tempers of the same alloy which result in identical mechanical properties, the distinction between the tempers should be covered in suitable explanatory notes. Basic Temper Designations F As Fabricated. Applies to the products that acquire some temper from shaping processes not having special control over the amount of strain-hardening or thermal treatment. O

Annealed Recrystallized (wrought products only). Applies to the softest temper of wrought products.

H

Strain-Hardened (wrought products only). Applies to products that have their strength increased by strain-hardening with or without supplementary thermal treatments to produce partial softening. The H is always followed by two or more digits. H1

Strain-Hardened Only. Applies to products that are strain-hardened to obtain the desired mechanical properties without supplementary thermal treatment. The number following this designation indicates the degree of strain-hardening.

H2

Strain-Hardened and Then Partially Annealed. Applies to products which are strain-hardened more than the desired final amount and then reduced in strength to the desired final amount by partial annealing. The number following this designation indicates the degree of strain-hardening remaining after the product has been partially annealed.

H3

Strain-Hardened and Stabilized. Applies to products that are strain-hardened and then stabilized by a low temperature heating to slightly lower their strength and increase ductility. This designation applies only to alloys which, unless stabilized, gradually age soften at room temperature. The number following this designation indicates the degree of strain-hardening remaining after the product has been strain-hardened a specific amount and then stabilized.

Subdivisions of the “H1", “H2" and “H3" Tempers: The digit following the designations “H1", “H2", and “H3" indicates the final degree of strain hardening. Tempers between 0 (annealed) and 8 (full hard) are designated by numerals 1 through 7. Material having a strength about midway between that of the 0 temper and that of the 8 temper is designated by the numeral 4 (half hard); between 0 and 4 by the numeral 2 (quarter hard); between 4 and 8 by the numeral 6 (three-quarter

a From ASTM B 296-96.

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MMPDS-01 31 January 2003 Table 4.1.5. Temper Designation System for Magnesium Alloys (Continued)a

hard), etc. The third digit, when used, indicates a variation of a two-digit H temper. It is used when the degree of control of temper or the mechanical properties are different from but close to those for the two-digit H temper to which it is added. Numerals 1 through 9 may be arbitrarily assigned as the third digit for an alloy and product to indicate a specific degree of control of temper or special mechanical property limits. 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 ½ hr.

T

Thermally Treated to Product Stable Tempers Other Than F, O, or H. Applies to products which are thermally treated, with or without supplementary strain-hardening, to product stable tempers. The T is always followed by one or more digits. Numerals 1 through 10 have been assigned to indicate specific sequences of basic treatments, as follows. T1

Cooled from an Elevated Temperature Shaping Process and Naturally Aged to a Substantially Stable Condition. Applies to products for which the rate of cooling from an elevated temperature shaping process, such as casting or extrusion, is such that their strength is increased by room temperature aging.

T3

Solution Heat-treated and Then Cold Worked. Applies to products that are cold worked to improve strength, or in which the effect of cold work in flattening and straightening is recognized in applicable mechanical properties.

T4

Solution Heat-treated and Naturally Aged to a Substantially Stable Condition. Applies to products that 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 applicable mechanical properties.

T5

Cooled from an Elevated-Temperature Shaping Process and Then Artificially Aged. Applies to products which are cooled from an elevated-temperature shaping process, such as casting or extrusion, and then artificially aged to improve mechanical properties or dimensional stability or both.

T6

Solution Heat-treated and Then Artificially Aged. Applies to products that are not cold worked after solution heat-treatment, or in which the effect of cold work is flattening or straightening may not be recognized in applicable mechanical properties.

T7

Solution Heat-treated and Then Stabilized. Applies to products that are stabilized to carry them beyond the point of maximum strength to provide control of some special characteristics.

T8

Solution Heat-treated, Cold Worked, and Then 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 applicable mechanical properties.

T9

Solution Heat-treated, Artificially Aged, and Then Cold Worked. Applies to products that are cold worked to improve strength.

a From ASTM B 296-96.

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MMPDS-01 31 January 2003 Table 4.1.5. Temper Designation System for Magnesium Alloys (Continued)a

T10

Cooled from an Elevated Temperature Shaping Process, Artificially Aged, and Then Cold Worked. Applies to products which are artificially aged after cooling from an elevated temperature shaping process, such as extrusion, and then cold worked to further improve strength.

A period of natural aging at room temperature may occur between or after the operations listed for tempers T3 through T10. Control of this period is exercised when it is metallurgically important. Additional digits, may be added to designations T1 through T10 to indicate a variation in treatment that significantly alters the characteristics of the product. a From ASTM B 296-96.

4.1.6 JOINING METHODS — Most magnesium alloys may be welded; refer to “Comments and Properties” in individual alloy sections. Adhesive bonding and brazing may be used to join magnesium to itself or other alloys. All types of mechanical fasteners may be used to join magnesium. Refer to Section 4.1.4 when using mechanical fasteners or joining of dissimilar materials with magnesium alloys.

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MMPDS-01 31 January 2003

4.2

MAGNESIUM-WROUGHT ALLOYS 4.2.1 AZ31B

4.2.1.0 Comments and Properties — AZ31B is a wrought magnesium-base alloy containing aluminum and zinc. It is available in the form of sheet, plate, extruded sections, forgings, and tubes. AZ31B has good room-temperature strength and ductility and is used primarily for applications where the temperature does not exceed 300EF. Increased strength is obtained in the sheet and plate form by strain hardening with a subsequent partial anneal (H24 and H26 temper). No treatments are available for increasing the strength of this alloy after fabrication. Forming of AZ31B must be done at elevated temperatures if small radii or deep draws are required. If the temperatures used are too high or the times too great, H24 and H26 temper material will be softened. This alloy is readily welded but must be stress relieved after welding to prevent stress corrosion cracking. Material specifications covering AZ31B wrought products are given in Table 4.2.1.0(a). Roomtemperature mechanical and physical properties are shown in Tables 4.2.1.0(b) through (d). The effect of temperature on physical properties is shown in Figure 4.2.1.0. Table 4.2.1.0(a). Material Specifications for AZ31B Magnesium Alloy

Specification AMS 4375 AMS 4376 AMS 4377 ASTM B 107 ASTM B 91

Form Sheet and plate Plate Sheet and plate Extrusion Forging

The temper index for AZ31B is as follows: Temper O H24 H26 F

Section 4.2.1.1 4.2.1.2 4.2.1.3 4.2.1.4

4.2.1.1 AZ31B-O Temper — Effect of temperature on the tensile modulus of sheet and plate is presented in Figure 4.2.1.1.4. Typical room-temperature stress-strain and tangent-modulus curves are presented in Figure 4.2.1.1.6. 4.2.1.2 AZ31B-H24 Temper — Effect of temperature on the mechanical properties of sheet and plate is shown in Figures 4.2.1.2.1 through 4.2.1.2.4, and 4.2.1.2.6. Typical room-temperature tension and compression stress-strain and tangent-modulus curves for sheet are shown in Figure 4.2.1.2.6. 4.2.1.3 AZ31B-H26 Temper 4.2.1.4 AZ31B-F Temper — Figures 4.2.1.4.8 (a) and (b) contain fatigue data for forged disk at room temperature.

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MMPDS-01 31 January 2003

Table 4.2.1.0(b). Design Mechanical and Physical Properties of AZ31B Magnesium Alloy Sheet and Plate

Specification . . . . . . . Form . . . . . . . . . . . . . . Temper . . . . . . . . . . . . Thickness, in. . . . . . . . Basis . . . . . . . . . . . . . . Mechanical Properties: Ftu, ksi: L .............. LT . . . . . . . . . . . . . Fty, ksi: L .............. LT . . . . . . . . . . . . . Fcy, ksi: L .............. LTa . . . . . . . . . . . . . Fsu, ksi . . . . . . . . . . . Fbrub, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . Fbryb, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . e, percent . . . . . . . . . L ..............

AMS 4375 Sheet Plate 0

AMS 4377 Plate H24

Sheet

0.016- 0.061- 0.250- 0.501- 2.001- 0.016- 0.063- 0.250- 0.375- 0.501- 1.0010.060 0.249 0.500 2.000 3.000 0.062 0.249 0.374 0.500 1.000 2.000

2.0013.000

S

S

S

S

S

S

S

S

S

S

S

S

32 ...

32 ...

32 ...

32 ...

32 ...

39 40

39 40

38 39

37 38

36 37

34 35

34 ...

18 ...

15 ...

15 ...

15 ...

15 ...

29 32

29 32

26 29

24 27

22 25

20 23

18 ...

... ... 17

12 ... 17

10 ... 17

10 ... ...

8 ... ...

... ... 18

24 ... 18

20 ... 18

16 ... 18

13 ... ...

10 ... ...

9 ... ...

50 60

50 60

50 60

... ...

... ...

58 68

58 68

56 65

54 63

... ...

... ...

... ...

29 29

29 29

27 27

... ...

... ...

43 43

43 43

38 38

34 34

... ...

... ...

... ...

12

12

12

10

9

6

6

8

8

8

8

8

3

E, 10 ksi . . . . . . . . . Ec, 103 ksi . . . . . . . . G, 103 ksi . . . . . . . . . µ ............... Physical Properties: ω, lb/in.3 . . . . . . . . . C, K, and α . . . . . . .

6.5 6.5 2.4 0.35 0.0639 See Figure 4.2.1.0

a Fcy(LT) allowables are equal to or greater than Fcy(L) allowables. b Bearing values are “dry pin” values per Section 1.4.7.1.

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MMPDS-01 31 January 2003

Table 4.2.1.0(c). Design Mechanical and Physical Properties of AZ31B Magnesium Alloy Plate

Specification . . . . . . . Form . . . . . . . . . . . . . . Temper . . . . . . . . . . . . Thickness, in. . . . . . . . Basis . . . . . . . . . . . . . . Mechanical Properties: Ftu, ksi: L .............. LT . . . . . . . . . . . . . Fty, ksi: L .............. LT . . . . . . . . . . . . . Fcy, ksi: L .............. LTa . . . . . . . . . . . . . Fsu, ksi . . . . . . . . . . . Fbrub, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . Fbryb, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . e, percent: L .............. E, 103 ksi . . . . . . . . . Ec, 103 ksi . . . . . . . . G, 103 ksi . . . . . . . . . µ ............... Physical Properties: ω, lb/in.3 . . . . . . . . . C, K, and α . . . . . . .

0.2500.375 S

0.3760.438 S

0.4390.500 S

AMS 4376 Plate H26 0.5010.750 S

39 40

38 39

38 39

37 38

37 38

35 36

35 36

27 30

26 29

26 29

25 28

23 26

22 25

21 24

22 ... 18

21 ... 18

18 .... 18

17 ... ...

16 ... ...

15 ... ...

14 ... ...

58 68

56 65

56 65

... ...

... ...

... ...

... ...

40 40

39 39

36 36

... ...

... ...

... ...

... ...

6

6

6

6 6.5 6.5 2.4 0.35

6

6

6

0.7511.000 S

1.0011.500 S

1.5012.000 S

0.0639 See Figure 4.2.1.0

a Fcy(LT) allowables are equal to or greater than Fcy(L) values. b Bearing values are "dry pin" values per Section 1.4.7.1.

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MMPDS-01 31 January 2003

Table 4.2.1.0(d). Design Mechanical and Physical Properties of AZ31B Magnesium Alloy Extrusion and Forging

Specification . . . . . . . Form . . . . . . . . . . . . . . Temper . . . . . . . . . . . . Thickness, in. . . . . . . . Basis . . . . . . . . . . . . . . Mechanical Properties: Ftu, ksi: L .............. LT . . . . . . . . . . . . . Fty, ksi: L .............. LT . . . . . . . . . . . . . Fcy, ksi: L .............. LT . . . . . . . . . . . . . Fsu, ksi . . . . . . . . . . . Fbrub, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . Fbryb, ksi: (e/D = 1.5) . . . . . . . (e/D = 2.0) . . . . . . . e, percent: L .............. E, 103 ksi . . . . . . . . . Ec, 103 ksi . . . . . . . . G, 103 ksi . . . . . . . . . µ ............... Physical Properties: ω, lb/in.3 . . . . . . . . . C, K, and α . . . . . . .

ASTM B 107 ASTM B 91 Extruded bar, rod, and Extruded Extruded tube Forging solid shapes hollow shapes F 0.250- 1.500- 2.5000.028- 0.251#0.249 ... All 1.499 2.499 4.999 0.250b 0.750b S S S S S S S S

35 ...

35 ...

34 ...

32 ...

32 ...

32 ...

32 ...

34 ...

21 ...

22 ...

22 ...

20 ...

16 ...

16 ...

16 ...

19 ...

... ... 17

12 ... 17

12 ... 17

10 ... ...

10 ... ...

10 ... ...

10 ... ...

... ... ...

36 45

36 45

36 45

... ...

... ...

... ...

... ...

... ...

23 23

23 23

23 23

... ...

... ...

... ...

... ...

... ...

7

7

7

7

8

8

4

6

6.5 6.5 2.4 0.35 0.0639 See Figure 4.2.1.0

a Wall thickness for tube; for outside diameter # 6.000 inches. b Bearing values are “dry pin” values per Section 1.4.7.1.

4-9

0.50

200

0.45

180

0.40

160

0.35

140

K, Btu/ [ (hr)(ft2)(°F)/ft]

120

C, Btu/ (lb)(°F)

220

α - Between 70 °F and indicated temperature K - At indicated temperature C - At indicated temperature

18 16

α

14 12

0.30 C

0.25

100

0.20

80

0.15 K, O & H24

60

0.10

40

0.05

20

0.00

-400

-200

0

200

400

600

800

1000

Temperature, °F Figure 4.2.1.0. Effect of temperature on the physical properties of AZ31B.

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α, 10-6 in./in./°F

MMPDS-01 31 January 2003

MMPDS-01 31 January 2003

Figure 4.2.1.1.4. Effect of temperature on the tensile modulus (E) of AZ31B-O sheet and plate.

25 Tension

20

Compression

Stress, ksi

15

10

Ramberg - Osgood n (L-tension) = 12 n (L-comp.) = 30

5

TYPICAL

0 0

2

4

6 8 Strain, 0.001 in./in. 3 Compressive Tangent Modulus, 10 ksi

10

12

Figure 4.2.1.1.6. Typical tensile and compressive stress-strain and compressive tangent-modulus curves for AZ31B-O sheet and plate at room temperature.

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MMPDS-01 31 January 2003

Figure 4.2.1.2.1. Effect of temperature on the tensile ultimate strength (Ftu) and the tensile yield strength (Fty) of AZ31B-H24 sheet and plate.

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MMPDS-01 31 January 2003

Figure 4.2.1.2.2. Effect of temperature on the compressive yield strength (Fcy) and the shear ultimate strength (Fsu) of AZ31B-H24 sheet and plate.

Figure 4.2.1.2.3. Effect of temperature on the bearing ultimate strength (Fbru) and the bearing yield strength (Fbry) of AZ31B-H24 sheet and plate.

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MMPDS-01 31 January 2003

Figure 4.2.1.2.4. Effect of temperature on the tensile modulus (E) of AZ31B-H24 sheet and plate.

50

40

Tension

Stress, ksi

30 Compression

20

Ramberg - Osgood n (tension) = 4.3 n (comp.) = 15

10

TYPICAL

0 0

2

4

6

8

10

12

Strain, 0.001 in./in. 3 Compressive Tangent Modulus, 10 ksi

Figure 4.2.1.2.6. Typical tensile and compressive stress-strain and compressive tangent-modulus curves for AZ31B-H24 sheet at room temperature.

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MMPDS-01 31 January 2003

Figure 4.2.1.4.8(a). Best-fit S/N curves for unnotched AZ31B-F magnesium alloy forged disk, transverse direction.

Correlative Information for Figure 4.2.1.4.8(a) Product Form: Forged disk, 1 inch thick

No. of Heats/Lots: 1

Properties:

Equivalent Stress Equation:

TUS, ksi 38

TYS, ksi 26

Temp.,EF RT

Specimen Details: Unnotched 0.75 inch gross diameter 0.30 inch net diameter Surface Condition: Polished sequentially with No. 320 aluminum oxide cloth, No. 0, 00, and 000 emery paper and finally No. 600 aluminum oxide powder in water References:

4.2.1.1.8

Test Parameters: Loading - Axial Frequency - 1500 cpm Temperature - RT Environment - Air

For R values between -1.0 and -0.50 Log Nf = 7.13-2.20 log (Seq-12.9) Seq = Smax(1-R)0.56 Std. Error of Estimate, Log (Life) = 0.613 Standard Deviation, Log (Life) = 0.916 R2 = 55.2% For R values between 0.0 and 0.50 Log Nf = 8.87-3.26 log (Seq-15.0) Seq = Smax(1-R)0.33 Std. Error of Estimate, Log (Life) = 0.829 Standard Deviation, Log (Life )= 1.014 R2 = 33.2% Sample Size = 194 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.]

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MMPDS-01 31 January 2003

Figure 4.2.1.4.8(b). Best-fit S/N curves for notched, Kt = 3.3, AZ31B-F magnesium alloy forged disk, transverse direction.

Correlative Information for Figure 4.2.1.4.8(b) Product Form: Forged disk, 1 inch thick Properties:

TUS, ksi 38

TYS, ksi 26

Test Parameters: Loading - Axial Frequency - 1500 cpm Temperature - RT Environment - Air

Temp.,EF RT

Specimen Details: Notched, Kt = 3.3 0.350 inch gross diameter 0.280 inch net diameter 0.010 inch root radius, r 60E flank angle, ω Reference:

No. of Heats/Lots: 1 Maximum Stress Equation: Log Nf = 8.28-4.34 log (Smax) Std. Error of Estimate, Log (Life) = 0.534 Standard Deviation, Log (Life) = 0.707 R2 = 43%

4.2.1.1.8

Sample Size = 34

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MMPDS-01 31 January 2003 4.2.2 AZ61A 4.2.2.0 Comments and Properties — AZ61A is a wrought magnesium-base alloy containing aluminum and zinc. It is available in the form of extruded sections, tubes, and forgings in the as-fabricated (F) temper. AZ61A is much like AZ31B in general characteristics. The increased aluminum content increases the strength and decreases the ductility slightly. Severe forming must be done at elevated temperatures. This alloy is readily welded but must be stress relieved after welding to prevent stress corrosion cracking. Material specifications covering AZ61A are given in Table 4.2.2.0(a). Room-temperature mechanical and physical properties are shown in Table 4.2.2.0(b).

Table 4.2.2.0(a). Material Specifications for AZ61A Magnesium Alloy

Specification

Form

AMS 4350 ASTM B 91

Extrusion Forging

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MMPDS-01 31 January 2003

Table 4.2.2.0(b). Design Mechanical and Physical Properties of AZ61A Magnesium Alloy Extrusion and Forging

Specification . . . . . . . . Form . . . . . . . . . . . . . . .

AMS 4350 Extruded bar, rod, and solid shapes

Temper . . . . . . . . . . . . .

Extruded hollow shapes F

Extruded tube

Forging

S

0.0280.750b S

40 ...

36 ...

36 ...

38 ...

24 ...

22 ...

16 ...

16 ...

22 ...

14 ... 19

14 ... 19

14 ... ...

11 ... ...

11 ... ...

14 ... 19

45 55

45 55

... ...

... ...

... ...

50 60

28 32

28 32

... ...

... ...

... ...

28 32

8

9

7

7

7

6

S

0.2502.499 S

2.5004.499a S

38 ...

40 ...

21 ...

Thickness, in. . . . . . . . .

#0.249

Basis . . . . . . . . . . . . . . . Mechanical Properties: Ftu, ksi: L ............... LT . . . . . . . . . . . . . . Fty, ksi: L ............... LT . . . . . . . . . . . . . . Fcy, ksi: L ............... LT . . . . . . . . . . . . . . Fsu, ksi . . . . . . . . . . . . Fbruc, ksi: (e/D = 1.5) . . . . . . . . (e/D = 2.0) . . . . . . . . Fbryc, ksi: (e/D = 1.5) . . . . . . . . (e/D = 2.0) . . . . . . . . e, percent: L ............... E, 103 ksi . . . . . . . . . . Ec, 103 ksi . . . . . . . . . G, 103 ksi . . . . . . . . . . µ ................ Physical Properties: ω, lb/in.3 . . . . . . . . . . C, Btu/(lb)(EF) . . . . . K, Btu/[(hr)(ft2)(EF)/ft] α, 10-6 in./in./EF . . . . . a b c d

ASTM B 91

All

6.3 6.3 2.4 0.31 0.0647 0.25 (at 78EF)d 46 (212 to 572EF) 14 (65 to 212EF)

For cross-sectional area #25 square inches. Wall thickness for outside diameters #6.000 inches. Bearing values are “dry pin” values per Section 1.4.7.1. Estimated.

4-18

... S

MMPDS-01 31 January 2003 4.2.3 ZK60A 4.2.3.0 Comments and Properties — ZK60A is a wrought magnesium-base alloy containing zinc and zirconium. It is available as extruded sections, tubes, and forgings. Increased strength is obtained by artificial aging (T5) from the as-fabricated (F) temper. ZK60A has the best combination of high roomtemperature strength and ductility of the wrought magnesium-base alloys. It is used primarily at temperatures below 300EF. ZK60A has good ductility as compared with other high-strength magnesium alloys and can be formed or bent cold into shapes not possible with those alloys having less ductility. It is not considered a weldable alloy. Material specifications for ZK60A are given in Table 4.2.3.0(a). Room-temperature mechanical and physical properties are shown in Tables 4.2.3.0(b) and (c). Elevated temperature curves for physical properties are shown in Figures 4.2.3.0. Table 4.2.3.0(a). Material Specifications for ZK60A Magnesium Alloy

Specification ASTM B 107 AMS 4352 AMS 4362

Form Extrusion Extrusion Die and hand forgings

The temper index for ZK60A is as follows: Temper F T5

Section 4.2.3.1 4.2.3.2 4.2.3.1 ZK60A-F Temper

4.2.3.2 ZK60A-T5 Temper — Typical room-temperature tension and compression stressstrain curves for extrusions are shown in Figures 4.2.3.2.6(a) and (b). Fatigue curves are presented in Figure 4.2.3.2.8(a) through (c).

4-19

MMPDS-01 31 January 2003

Table 4.2.3.0(b). Design Mechanical and Physical Properties of ZK60A Magnesium Alloy Extrusion

Specification . . . . . . . . . . .

ASTM B 107

Form . . . . . . . . . . . . . . . . . . Temper . . . . . . . . . . . . . . . . Cross-sectional area, in.2 . . . . . . . . . . . . . . . . . . .

Extruded Extruded hollow shapes tube

Extruded rod, bar, and solid shapes