Type 3 (Alloyed Reactor Grade, R04251) Niobium
Type 3 niobium is a niobium alloy. Cited properties are appropriate for the annealed condition. R04251 is the UNS number for this material. Additionally, the ASTM designation is Niobium Type 3. It has a moderately low density among the alloys in the same category in the database.
The graph bars on the material properties cards below compare Type 3 niobium to: niobium alloys (top), all alloys in the same category (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Brinell Hardness
110
Elastic (Young's, Tensile) Modulus
100 GPa 15 x 106 psi
Elongation at Break
23 %
Poisson's Ratio
0.4
Shear Modulus
38 GPa 5.4 x 106 psi
Tensile Strength: Ultimate (UTS)
220 MPa 32 x 103 psi
Tensile Strength: Yield (Proof)
140 MPa 20 x 103 psi
Thermal Properties
Latent Heat of Fusion
310 J/g
Specific Heat Capacity
270 J/kg-K 0.065 BTU/lb-°F
Thermal Conductivity
42 W/m-K 24 BTU/h-ft-°F
Thermal Expansion
7.3 µm/m-K
Otherwise Unclassified Properties
Density
8.6 g/cm3 530 lb/ft3
Embodied Water
160 L/kg 19 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
44 MJ/m3
Resilience: Unit (Modulus of Resilience)
93 kJ/m3
Stiffness to Weight: Axial
6.8 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
7.2 points
Strength to Weight: Bending
9.5 points
Thermal Diffusivity
18 mm2/s
Thermal Shock Resistance
21 points
Alloy Composition
| Nb | 98.6 to 99.2 | |
| Zr | 0.8 to 1.2 | |
| Ta | 0 to 0.1 | |
| W | 0 to 0.030 | |
| Ti | 0 to 0.020 | |
| Hf | 0 to 0.020 | |
| O | 0 to 0.015 | |
| C | 0 to 0.010 | |
| Mo | 0 to 0.010 | |
| N | 0 to 0.010 | |
| Si | 0 to 0.0050 | |
| Ni | 0 to 0.0050 | |
| Fe | 0 to 0.0050 | |
| H | 0 to 0.0015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B392: Standard Specification for Niobium and Niobium Alloy Bar, Rod, and Wire
ASTM B393: Standard Specification for Niobium and Niobium Alloy Strip, Sheet, and Plate
ASTM B394: Standard Specification for Niobium and Niobium Alloy Seamless and Welded Tubes
Extractive Metallurgy of Niobium, C. K. Gupta and A. K. Suri, 1993
Sintering of Advanced Materials: Fundamentals and Processes, Zhigang Zak Fang (editor), 2010