DMLS Ti-6Al-4V ELI Titanium vs. Magnesium AZ91D

Compare DMLS Ti-6Al-4V ELI Titanium vs. Magnesium AZ91D strength, stiffness, weight and thermal properties.

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DMLS Ti-6Al-4V ELI Titanium3D printed metal (DMLS)

Mechanical
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Yield strength	1,100MPasourcetypical, as built, average of horizontal + vertical (M400)	150MPasourcetypical, 0.2% tensile yield, ambient temperature
Ultimate tensile strength	1,270MPasourcetypical, as built, average of horizontal + vertical (M400)	230MPasourcetypical, ambient temperature
Elongation at break	8.7%sourcetypical at break, as built (M400)	3%sourcetypical, ambient temperature
Young's modulus (stiffness)	110GPasourcesame maker and process, sibling grade: EOS Titanium Ti64 (Grade 5) on EOS M 290, as built, XY and Z, typical	45GPasourcetypical
Density	4,400kg/m³sourcetypical part density (ISO 3369), M400	1,810kg/m³sourcetypical
Strength to weight	250kN·m/kg3.02x higher	82.9kN·m/kg
Stiffness to weight	25MN·m/kg	24.9MN·m/kg
Poisson's ratio	0.342sourcewrought TIMETAL 6-4 (TIMET measurement, mean of 10); composition-level, not DMLS-measured	0.35sourcebase material: AZ91C casting (MIL-HDBK-5J handbook physical constant)
Shear modulus	41GPa2.46x stiffer in shear	16.7GPa
Bulk modulus	116GPa	50GPa
Speed of sound	5,000m/s	4,986m/s
Thermal
Thermal conductivity	6.6W/m·Ksourcebase material: wrought Ti-6Al-4V / 6-4 ELI (TIMET datasheet), 20 °C	72W/m·Ksourcetypical
Thermal expansion	9µm/m·Ksourcemean 25-100 °C, ASTM E228; EOS Ti64 Grade 23 (=ELI) on EOS M 290 40 µm; condition not stated (sheet's mechanical data are heat treated)	25µm/m·Ksourcetypical, temperature range not stated
100 mm part over a 50 °C swing	45µm growth2.78x less	125µm growth
Specific heat	580J/kg·Ksourcebase material: wrought Ti-6Al-4V / 6-4 ELI (TIMET datasheet), 20 °C	1,050J/kg·Ksourcetypical
Heats up and cools (diffusivity)	2.59mm²/s	37.9mm²/s14.6x faster
Thermal shock resistance	4,825W/m	6,240W/m29% more resistant
Melting point	1,630–1,650°Csourcemelting range, wrought TIMETAL 6-4 (composition-level)	470–595°Csourcemelting range
Values for	EOS Titanium Ti64ELI (powder 9011-0040; ASTM F136/F3001, i.e. Grade 23) on EOS M400 SF, parameter set Ti64ELI_030_FlexM400_100, 30 µm, as built; ISO 6892-1 A14	ELEKTRON AZ91D magnesium die-casting alloy, as cast; Magnesium Elektron datasheet 475 (7/01), typical properties; Poisson from MIL-HDBK-5J for AZ91C castings.

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.

DMLS Ti-6Al-4V ELI Titanium is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is DMLS Ti-6Al-4V ELI Titanium stronger than Magnesium AZ91D?

DMLS Ti-6Al-4V ELI Titanium is stronger: its yield strength is 1,100 MPa against 150 MPa for Magnesium AZ91D (7.33x).

Which is lighter, DMLS Ti-6Al-4V ELI Titanium or Magnesium AZ91D?

Magnesium AZ91D is lighter: 1,810 kg/m³ against 4,400 kg/m³ for DMLS Ti-6Al-4V ELI Titanium.

Which is stiffer, DMLS Ti-6Al-4V ELI Titanium or Magnesium AZ91D?

DMLS Ti-6Al-4V ELI Titanium is stiffer: Young's modulus 110 GPa against 45 GPa for Magnesium AZ91D, so the same part in DMLS Ti-6Al-4V ELI Titanium deflects less under the same load.

Which is lighter for the same job, DMLS Ti-6Al-4V ELI Titanium or Magnesium AZ91D?

For the same stiffness or strength: DMLS Ti-6Al-4V ELI Titanium is lighter for a strong rod or tie, strong beam, strong panel or plate; Magnesium AZ91D is lighter for a stiff beam (bending), stiff panel or plate.

Part that must be	DMLS Ti-6Al-4V ELI Titanium	Magnesium AZ91D
Stiff rod or tie (tension)	about equal	about equal
Stiff beam (bending)	1.55x heavier	lighter
Stiff panel or plate	1.8x heavier	lighter
Strong rod or tie	lighter	3.02x heavier
Strong beam	lighter	1.55x heavier
Strong panel or plate	lighter	11% heavier

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, DMLS Ti-6Al-4V ELI Titanium or Magnesium AZ91D?

Magnesium AZ91D conducts heat better: 72 W/m·K against 6.6 W/m·K for DMLS Ti-6Al-4V ELI Titanium.

Which expands less with temperature?

DMLS Ti-6Al-4V ELI Titanium expands less: 9 µm/m·K against 25 µm/m·K for Magnesium AZ91D.

Among 72 materials

Stiffness against density

Strength against density