ASTM A369 Grade FPA vs. 90-platinum 10-iridium
ASTM A369 grade FPA belongs to the iron alloys classification, while 90-platinum 10-iridium belongs to the otherwise unclassified metals. There are 15 material properties with values for both materials. Properties with values for just one material (16, 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 ASTM A369 grade FPA and the bottom bar is 90-platinum 10-iridium.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 27 | |
| 5.5 to 34 |
| Poisson's Ratio | 0.29 | |
| 0.38 |
| Shear Modulus, GPa | 73 | |
| 74 |
| Shear Strength, MPa | 240 | |
| 220 to 320 |
| Tensile Strength: Ultimate (UTS), MPa | 380 | |
| 330 to 550 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 100 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 130 |
| Thermal Expansion, µm/m-K | 12 | |
| 8.6 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 22 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 5.3 |
| Stiffness to Weight: Bending, points | 24 | |
| 9.1 |
| Strength to Weight: Axial, points | 13 | |
| 4.2 to 7.1 |
| Strength to Weight: Bending, points | 15 | |
| 4.9 to 6.9 |
| Thermal Shock Resistance, points | 12 | |
| 13 to 22 |
Alloy Composition
| Carbon (C), % | 0 to 0.25 | |
| 0 |
| Iridium (Ir), % | 0 | |
| 9.5 to 10.5 |
| Iron (Fe), % | 98.3 to 99.63 | |
| 0 |
| Manganese (Mn), % | 0.27 to 0.93 | |
| 0 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 |
| Platinum (Pt), % | 0 | |
| 89.3 to 90.5 |
| Silicon (Si), % | 0.1 to 0.5 | |
| 0 |
| Sulfur (S), % | 0 to 0.035 | |
| 0 |
| Residuals, % | 0 | |
| 0 to 0.2 |