# 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 10 ^{6} psi*

Elongation at Break

17 *%*

Fatigue Strength

620 *MPa* 91 *x 10 ^{3} psi*

Poisson's Ratio

0.32

Reduction in Area

22 *%*

Shear Modulus

51 *GPa* 7.5 *x 10 ^{6} psi*

Shear Strength

680 *MPa* 98 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

1100 *MPa* 160 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

970 *MPa* 140 *x 10 ^{3} 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*

Density

5.4 *g/cm ^{3}* 340

*lb/ft*

^{3}Embodied Carbon

32 *kg CO _{2}/kg material*

Embodied Energy

490 *MJ/kg* 210 *x 10 ^{3} BTU/lb*

Embodied Water

180 *L/kg* 21 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

180 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

3490 *kJ/m ^{3}*

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 *mm ^{2}/s*

Thermal Shock Resistance

82 *points*

## Alloy Composition

Ti | 76 to 81.2 | |

Mo | 14 to 16 | |

Al | 2.5 to 3.5 | |

Nb | 2.2 to 3.2 | |

Si | 0.15 to 0.25 | |

Fe | 0 to 0.4 | |

O | 0 to 0.17 | |

C | 0 to 0.050 | |

N | 0 to 0.030 | |

H | 0 to 0.015 | |

res. | 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