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Solution-Treated and Aged (Moderate Strength) Grade 21 Titanium

Moderate strength grade 21 titanium is grade 21 titanium in the annealed and aged condition. The graph bars on the material properties cards below compare moderate strength grade 21 titanium to: wrought titaniums (top), all titanium alloys (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

140 GPa 20 x 106 psi

Elongation at Break

17 %

Fatigue Strength

620 MPa 91 x 103 psi

Poisson's Ratio


Reduction in Area

22 %

Shear Modulus

51 GPa 7.5 x 106 psi

Shear Strength

680 MPa 98 x 103 psi

Tensile Strength: Ultimate (UTS)

1100 MPa 160 x 103 psi

Tensile Strength: Yield (Proof)

970 MPa 140 x 103 psi

Thermal Properties

Latent Heat of Fusion

410 J/g

Maximum Temperature: Mechanical

310 °C 590 °F

Melting Completion (Liquidus)

1740 °C 3170 °F

Melting Onset (Solidus)

1690 °C 3070 °F

Specific Heat Capacity

500 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

7.5 W/m-K 4.3 BTU/h-ft-°F

Thermal Expansion

7.1 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

60 % relative


5.4 g/cm3 340 lb/ft3

Embodied Carbon

32 kg CO2/kg material

Embodied Energy

490 MJ/kg 210 x 103 BTU/lb

Embodied Water

180 L/kg 21 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

180 MJ/m3

Resilience: Unit (Modulus of Resilience)

3490 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

32 points

Strength to Weight: Axial

57 points

Strength to Weight: Bending

44 points

Thermal Diffusivity

2.8 mm2/s

Thermal Shock Resistance

82 points

Alloy Composition

Titanium (Ti)Ti 76 to 81.2
Molybdenum (Mo)Mo 14 to 16
Aluminum (Al)Al 2.5 to 3.5
Niobium (Nb)Nb 2.2 to 3.2
Silicon (Si)Si 0.15 to 0.25
Iron (Fe)Fe 0 to 0.4
Oxygen (O)O 0 to 0.17
Carbon (C)C 0 to 0.050
Nitrogen (N)N 0 to 0.030
Hydrogen (H)H 0 to 0.015
Residualsres. 0 to 0.4

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

Followup Questions

Further Reading

ASTM B861: Standard Specification for Titanium and Titanium Alloy Seamless Pipe

ASTM B381: Standard Specification for Titanium and Titanium Alloy Forgings

ASTM B265: Standard Specification for Titanium and Titanium Alloy Strip, Sheet, and Plate

ASTM B348: Standard Specification for Titanium and Titanium Alloy Bars and Billets

Titanium and Titanium Alloys: Fundamentals and Applications, Christoph Leyens and Manfred Peters (editors), 2003

Titanium, 2nd ed., G. Lutjering and J. C. Williams, 2007

Aerospace Materials, Brian Cantor et al. (editors), 2001