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7049 Aluminum vs. S21904 Stainless Steel

7049 aluminum belongs to the aluminum alloys classification, while S21904 stainless steel belongs to the iron alloys. There are 31 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.

For each property being compared, the top bar is 7049 aluminum and the bottom bar is S21904 stainless steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 140
210 to 300
Elastic (Young's, Tensile) Modulus, GPa 70
200
Elongation at Break, % 6.2 to 7.0
17 to 51
Fatigue Strength, MPa 160 to 170
380 to 550
Poisson's Ratio 0.32
0.28
Shear Modulus, GPa 27
78
Shear Strength, MPa 300 to 310
510 to 620
Tensile Strength: Ultimate (UTS), MPa 510 to 530
700 to 1000
Tensile Strength: Yield (Proof), MPa 420 to 450
390 to 910

Thermal Properties

Latent Heat of Fusion, J/g 370
290
Maximum Temperature: Mechanical, °C 180
980
Melting Completion (Liquidus), °C 640
1400
Melting Onset (Solidus), °C 480
1350
Specific Heat Capacity, J/kg-K 860
480
Thermal Conductivity, W/m-K 130
14
Thermal Expansion, µm/m-K 23
17

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 36
2.5
Electrical Conductivity: Equal Weight (Specific), % IACS 110
2.9

Otherwise Unclassified Properties

Base Metal Price, % relative 10
15
Density, g/cm3 3.1
7.7
Embodied Carbon, kg CO2/kg material 8.1
3.0
Embodied Energy, MJ/kg 140
43
Embodied Water, L/kg 1110
160

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 31 to 34
160 to 310
Resilience: Unit (Modulus of Resilience), kJ/m3 1270 to 1440
380 to 2070
Stiffness to Weight: Axial, points 13
14
Stiffness to Weight: Bending, points 45
25
Strength to Weight: Axial, points 46 to 47
25 to 36
Strength to Weight: Bending, points 46 to 47
23 to 29
Thermal Diffusivity, mm2/s 51
3.8
Thermal Shock Resistance, points 22 to 23
15 to 21

Alloy Composition

Aluminum (Al), % 85.7 to 89.5
0
Carbon (C), % 0
0 to 0.040
Chromium (Cr), % 0.1 to 0.22
19 to 21.5
Copper (Cu), % 1.2 to 1.9
0
Iron (Fe), % 0 to 0.35
59.5 to 67.4
Magnesium (Mg), % 2.0 to 2.9
0
Manganese (Mn), % 0 to 0.2
8.0 to 10
Nickel (Ni), % 0
5.5 to 7.5
Nitrogen (N), % 0
0.15 to 0.4
Phosphorus (P), % 0
0 to 0.045
Silicon (Si), % 0 to 0.25
0 to 1.0
Sulfur (S), % 0
0 to 0.030
Titanium (Ti), % 0 to 0.1
0
Zinc (Zn), % 7.2 to 8.2
0
Residuals, % 0 to 0.15
0