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Nuclear Grade (Grade R1) Hafnium

Nuclear grade hafnium is a hafnium alloy. Cited properties are appropriate for the annealed condition. It has a fairly low heat capacity and a moderately high density among alloys in the same category.

The graph bars on the material properties cards below compare nuclear grade hafnium to: hafnium 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

Elastic (Young's, Tensile) Modulus

78 GPa 11 x 106 psi

Elongation at Break

25 %

Poisson's Ratio


Shear Modulus

31 GPa 4.5 x 106 psi

Tensile Strength: Ultimate (UTS)

350 MPa 51 x 103 psi

Tensile Strength: Yield (Proof)

170 MPa 25 x 103 psi

Other Material Properties


13 g/cm3 830 lb/ft3

Latent Heat of Fusion

130 J/g

Specific Heat Capacity

140 J/kg-K 0.034 BTU/lb-°F

Thermal Expansion

5.9 µm/m-K

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

73 MJ/m3

Resilience: Unit (Modulus of Resilience)

180 kJ/m3

Stiffness to Weight: Axial

3.3 points

Stiffness to Weight: Bending

11 points

Strength to Weight: Axial

7.4 points

Strength to Weight: Bending

8.4 points

Thermal Shock Resistance

55 points

Alloy Composition

Hafnium (Hf)Hf 99.8 to 100
Residualsres. 0 to 0.23

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Further Reading

ASTM B737: Standard Specification for Hot-Rolled and/or Cold-Finished Hafnium Rod and Wire

ASTM B776: Standard Specification for Hafnium and Hafnium Alloy Strip, Sheet, and Plate