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Stress Relieved UNS R05200 Cast Unalloyed Tantalum

Stress relieved R05200 tantalum is R05200 tantalum in the stress relieved condition. The graph bars on the material properties cards below compare stress relieved R05200 tantalum to: tantalum 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

190 GPa 27 x 106 psi

Elongation at Break

5.7 %

Poisson's Ratio


Shear Modulus

69 GPa 10 x 106 psi

Tensile Strength: Ultimate (UTS)

430 MPa 63 x 103 psi

Tensile Strength: Yield (Proof)

270 MPa 39 x 103 psi

Thermal Properties

Latent Heat of Fusion

140 J/g

Melting Completion (Liquidus)

3020 °C 5460 °F

Specific Heat Capacity

140 J/kg-K 0.034 BTU/lb-°F

Thermal Conductivity

59 W/m-K 34 BTU/h-ft-°F

Thermal Expansion

6.5 µm/m-K

Otherwise Unclassified Properties


17 g/cm3 1040 lb/ft3

Embodied Water

650 L/kg 77 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

22 MJ/m3

Resilience: Unit (Modulus of Resilience)

200 kJ/m3

Stiffness to Weight: Axial

6.2 points

Stiffness to Weight: Bending

11 points

Strength to Weight: Axial

7.2 points

Strength to Weight: Bending

7.6 points

Thermal Diffusivity

25 mm2/s

Thermal Shock Resistance

26 points

Alloy Composition

Tantalum (Ta)Ta 99.8 to 100
Niobium (Nb)Nb 0 to 0.1
Tungsten (W)W 0 to 0.050
Molybdenum (Mo)Mo 0 to 0.020
Oxygen (O)O 0 to 0.015
Carbon (C)C 0 to 0.010
Nickel (Ni)Ni 0 to 0.010
Iron (Fe)Fe 0 to 0.010
Nitrogen (N)N 0 to 0.010
Titanium (Ti)Ti 0 to 0.010
Silicon (Si)Si 0 to 0.0050
Hydrogen (H)H 0 to 0.0015

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

Followup Questions

Further Reading

ASTM F560: Standard Specification for Unalloyed Tantalum for Surgical Implant Applications (UNS R05200, UNS R05400)

ASTM B365: Standard Specification for Tantalum and Tantalum Alloy Rod and Wire

ASTM B521: Standard Specification for Tantalum and Tantalum Alloy Seamless and Welded Tubes

ASTM B708: Standard Specification for Tantalum and Tantalum Alloy Plate, Sheet, and Strip