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2218 Aluminum vs. AISI 308 Stainless Steel

2218 aluminum belongs to the aluminum alloys classification, while AISI 308 stainless steel belongs to the iron alloys. There are 31 material properties with values for both materials. Properties with values for just one material (4, 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 2218 aluminum and the bottom bar is AISI 308 stainless steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 95 to 110
160
Elastic (Young's, Tensile) Modulus, GPa 73
200
Elongation at Break, % 6.8 to 10
45
Fatigue Strength, MPa 110
210
Poisson's Ratio 0.33
0.28
Shear Modulus, GPa 27
78
Shear Strength, MPa 210 to 250
410
Tensile Strength: Ultimate (UTS), MPa 330 to 430
590
Tensile Strength: Yield (Proof), MPa 260 to 310
230

Thermal Properties

Latent Heat of Fusion, J/g 390
290
Maximum Temperature: Mechanical, °C 220
990
Melting Completion (Liquidus), °C 640
1420
Melting Onset (Solidus), °C 510
1380
Specific Heat Capacity, J/kg-K 870
480
Thermal Conductivity, W/m-K 140
15
Thermal Expansion, µm/m-K 22
16

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 37
2.4
Electrical Conductivity: Equal Weight (Specific), % IACS 110
2.8

Otherwise Unclassified Properties

Base Metal Price, % relative 11
17
Density, g/cm3 3.1
7.8
Embodied Carbon, kg CO2/kg material 8.2
3.2
Embodied Energy, MJ/kg 150
46
Embodied Water, L/kg 1130
150

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 27 to 31
210
Resilience: Unit (Modulus of Resilience), kJ/m3 450 to 650
140
Stiffness to Weight: Axial, points 13
14
Stiffness to Weight: Bending, points 45
25
Strength to Weight: Axial, points 30 to 39
21
Strength to Weight: Bending, points 34 to 41
20
Thermal Diffusivity, mm2/s 52
4.1
Thermal Shock Resistance, points 15 to 19
13

Alloy Composition

Aluminum (Al), % 88.8 to 93.6
0
Carbon (C), % 0
0 to 0.080
Chromium (Cr), % 0 to 0.1
19 to 21
Copper (Cu), % 3.5 to 4.5
0
Iron (Fe), % 0 to 1.0
64.1 to 71
Magnesium (Mg), % 1.2 to 1.8
0
Manganese (Mn), % 0 to 0.2
0 to 2.0
Nickel (Ni), % 1.7 to 2.3
10 to 12
Phosphorus (P), % 0
0 to 0.045
Silicon (Si), % 0 to 0.9
0 to 0.75
Sulfur (S), % 0
0 to 0.030
Zinc (Zn), % 0 to 0.25
0
Residuals, % 0 to 0.15
0