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UNS R04295 Niobium-Hafnium Alloy

R04295 alloy is a niobium alloy. Cited properties are appropriate for the annealed condition. 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 R04295 alloy 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

Elastic (Young's, Tensile) Modulus

100 GPa 15 x 106 psi

Elongation at Break

22 %

Poisson's Ratio


Shear Modulus

37 GPa 5.4 x 106 psi

Tensile Strength: Ultimate (UTS)

410 MPa 60 x 103 psi

Tensile Strength: Yield (Proof)

300 MPa 43 x 103 psi

Thermal Properties

Latent Heat of Fusion

300 J/g

Specific Heat Capacity

260 J/kg-K 0.062 BTU/lb-°F

Thermal Expansion

7.2 µm/m-K

Otherwise Unclassified Properties


9.0 g/cm3 560 lb/ft3

Embodied Water

950 L/kg 110 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

84 MJ/m3

Resilience: Unit (Modulus of Resilience)

430 kJ/m3

Stiffness to Weight: Axial

6.3 points

Stiffness to Weight: Bending

17 points

Strength to Weight: Axial

13 points

Strength to Weight: Bending

14 points

Thermal Shock Resistance

40 points

Alloy Composition

Niobium (Nb)Nb 85.9 to 90.3
Hafnium (Hf)Hf 9.0 to 11
Titanium (Ti)Ti 0.7 to 1.3
Zirconium (Zr)Zr 0 to 0.7
Tungsten (W)W 0 to 0.5
Tantalum (Ta)Ta 0 to 0.5
Oxygen (O)O 0 to 0.025
Carbon (C)C 0 to 0.015
Nitrogen (N)N 0 to 0.010
Hydrogen (H)H 0 to 0.0015

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

Followup Questions

Similar Alloys

Further Reading

ASTM B654: Standard Specification for Niobium-Hafnium Alloy Foil, Sheet, Strip, and Plate

ASTM B655: Standard Specification for Niobium-Hafnium Alloy Bar, Rod, and Wire

Extractive Metallurgy of Niobium, C. K. Gupta and A. K. Suri, 1993

Sintering of Advanced Materials: Fundamentals and Processes, Zhigang Zak Fang (editor), 2010