Nickel Inconel 718 vs. Titanium Ti-6Al-4V

Compare Nickel Inconel 718 vs. Titanium Ti-6Al-4V strength, stiffness, weight and thermal properties.

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Mechanical
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Yield strength	1,207MPasourcetypical, 1.0 in. hot-rolled bar, 0.2% offset	885MPasourcetypical, plate (>0.187 in), annealed, 0.2% offset
Ultimate tensile strength	1,389MPasourcetypical, 1.0 in. bar	940MPasourcetypical, plate, annealed
Elongation at break	20%sourcetypical, 1.0 in. bar	16%sourcetypical, in 2 in., plate annealed
Young's modulus (stiffness)	200GPasourcetypical, 21 °C, annealed + aged	107–122GPasourcetypical range, 20 °C
Density	8,221kg/m³sourcenominal, annealed and aged	4,430kg/m³sourcenominal
Strength to weight	147kN·m/kg	200kN·m/kg36% higher
Stiffness to weight	24.3MN·m/kg	25.8MN·m/kg6% higher
Poisson's ratio	0.294sourcetypical, 21 °C, annealed + aged	0.342sourcemean of TIMET measurements
Shear modulus	77.3GPa1.81x stiffer in shear	42.7GPa
Bulk modulus	162GPa	121GPa
Speed of sound	4,932m/s	5,084m/s
Thermal
Thermal conductivity	11.4W/m·Ksourcetypical, 21 °C, annealed + aged (calculated from resistivity per footnote a)	6.6W/m·Ksourcetypical, 20 °C, mill annealed
Thermal expansion	13.2µm/m·Ksourcetypical, mean 21-93 °C, annealed + aged	9µm/m·Ksourcetypical, mean 0-100 °C
100 mm part over a 50 °C swing	66µm growth	45µm growth47% less
Specific heat	435J/kg·Ksourcetypical, 21 °C	580J/kg·Ksourcetypical, 20 °C
Heats up and cools (diffusivity)	3.19mm²/s24% faster	2.57mm²/s
Thermal shock resistance	3,680W/m	3,730W/m1% more resistant
Melting point	1,260–1,336°Csourcemelting range	1,630–1,650°Csourcemelting range
Max service temperature	704°Csourceupper use temperature stated by producer	400°Csourceupper recommended use temperature
Values for	INCONEL alloy 718, standard grade, 1750 °F/1 hr anneal + 1325 °F/8 hr F.C. to 1150 °F aged; Special Metals bulletin SMC-045 typical values	TIMETAL 6-4 (Ti-6Al-4V Grade 5) annealed plate typical (TIMET properties manual) + TIMET datasheet TMC-0150 physical properties

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Nickel Inconel 718 stronger than Titanium Ti-6Al-4V?

Nickel Inconel 718 is stronger: its yield strength is 1,207 MPa against 885 MPa for Titanium Ti-6Al-4V (36%).

Which is lighter, Nickel Inconel 718 or Titanium Ti-6Al-4V?

Titanium Ti-6Al-4V is lighter: 4,430 kg/m³ against 8,221 kg/m³ for Nickel Inconel 718.

Which is stiffer, Nickel Inconel 718 or Titanium Ti-6Al-4V?

Nickel Inconel 718 is stiffer: Young's modulus 200 GPa against 115 GPa for Titanium Ti-6Al-4V, so the same part in Nickel Inconel 718 deflects less under the same load.

Which is lighter for the same job, Nickel Inconel 718 or Titanium Ti-6Al-4V?

For the same stiffness or strength: Titanium Ti-6Al-4V is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Nickel Inconel 718	Titanium Ti-6Al-4V
Stiff rod or tie (tension)	6% heavier	lighter
Stiff beam (bending)	40% heavier	lighter
Stiff panel or plate	1.54x heavier	lighter
Strong rod or tie	36% heavier	lighter
Strong beam	1.51x heavier	lighter
Strong panel or plate	1.59x heavier	lighter

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which conducts heat better, Nickel Inconel 718 or Titanium Ti-6Al-4V?

Nickel Inconel 718 conducts heat better: 11.4 W/m·K against 6.6 W/m·K for Titanium Ti-6Al-4V.

Which expands less with temperature?

Titanium Ti-6Al-4V expands less: 9 µm/m·K against 13.2 µm/m·K for Nickel Inconel 718.

Among 59 materials

Stiffness against density

Strength against density