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EN-MC65120 Magnesium vs. SAE-AISI 81B45 Steel

EN-MC65120 magnesium belongs to the magnesium alloys classification, while SAE-AISI 81B45 steel belongs to the iron alloys. 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 EN-MC65120 magnesium and the bottom bar is SAE-AISI 81B45 steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 55
160 to 200
Elastic (Young's, Tensile) Modulus, GPa 45
190
Elongation at Break, % 3.1
12 to 24
Fatigue Strength, MPa 80
250 to 350
Poisson's Ratio 0.29
0.29
Shear Modulus, GPa 17
73
Shear Strength, MPa 92
340 to 400
Tensile Strength: Ultimate (UTS), MPa 160
540 to 670
Tensile Strength: Yield (Proof), MPa 110
350 to 560

Thermal Properties

Latent Heat of Fusion, J/g 330
250
Maximum Temperature: Mechanical, °C 180
410
Melting Completion (Liquidus), °C 590
1460
Melting Onset (Solidus), °C 520
1420
Specific Heat Capacity, J/kg-K 970
470
Thermal Conductivity, W/m-K 100
40
Thermal Expansion, µm/m-K 26
12

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 25
7.2
Electrical Conductivity: Equal Weight (Specific), % IACS 120
8.3

Otherwise Unclassified Properties

Base Metal Price, % relative 25
2.3
Density, g/cm3 1.9
7.8
Embodied Carbon, kg CO2/kg material 25
1.5
Embodied Energy, MJ/kg 190
20
Embodied Water, L/kg 930
49

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 4.4
77 to 110
Resilience: Unit (Modulus of Resilience), kJ/m3 140
320 to 840
Stiffness to Weight: Axial, points 13
13
Stiffness to Weight: Bending, points 62
24
Strength to Weight: Axial, points 23
19 to 24
Strength to Weight: Bending, points 34
19 to 22
Thermal Diffusivity, mm2/s 56
11
Thermal Shock Resistance, points 9.8
17 to 21

Alloy Composition

Boron (B), % 0
0.00050 to 0.0030
Carbon (C), % 0
0.43 to 0.48
Chromium (Cr), % 0
0.35 to 0.55
Copper (Cu), % 0 to 0.030
0
Iron (Fe), % 0 to 0.010
97 to 98
Magnesium (Mg), % 91.8 to 95.1
0
Manganese (Mn), % 0 to 0.15
0.75 to 1.0
Molybdenum (Mo), % 0
0.080 to 0.15
Nickel (Ni), % 0 to 0.0050
0.2 to 0.4
Phosphorus (P), % 0
0 to 0.035
Silicon (Si), % 0 to 0.010
0.15 to 0.35
Sulfur (S), % 0
0 to 0.040
Unspecified Rare Earths, % 2.5 to 4.0
0
Zinc (Zn), % 2.0 to 3.0
0
Zirconium (Zr), % 0.4 to 1.0
0
Residuals, % 0 to 0.010
0