Aluminium-Silicon-Magnesium Alloy AlSi10Mg

Material Profile: Aluminium-Silicon-Magnesium Alloy AlSi10Mg for Direct Metal Laser Sintering

SLS Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—AlSi10Mg is a near-eutectic Al-Si casting alloy with a small magnesium addition, the dominant aluminium powder in laser powder-bed fusion (DMLS / SLM). The 9–11 wt% silicon content places the alloy near the Al-Si eutectic (12.6 wt%), giving low solidification shrinkage, narrow solidification range, and good fluidity in the melt pool — all of which favor dense, crack-free DMLS builds. The 0.2–0.45 wt% Mg enables age-hardening through precipitation of Mg₂Si, primarily via the T6 heat-treatment cycle. As-built AlSi10Mg achieves UTS ≈ 460 MPa (XY) and yield ≈ 270 MPa (XY) — comparable to T6-condition cast AlSi10Mg, because the laser-induced rapid solidification produces a fine cellular eutectic microstructure that already approximates the hardened condition. Stress-relief at 270 °C / 90 min recovers some elongation; full T6 (solution-treat + age) further homogenises properties. AlSi10Mg combines specific stiffness (~25 GPa/(g·cm⁻³)), corrosion resistance, weldability, and thermal conductivity (103–119 W/m·K) — the workhorse aluminium for LPBF heat-sinks, automotive ducts, and aerospace brackets.

Index Terms—additive manufacturing, direct metal laser sintering, DMLS, selective laser melting, SLM, AlSi10Mg, aluminium alloy, lightweight.

I.  MATERIAL IDENTIFICATION

This section establishes the canonical names and commercial designations under which the material is supplied.

A.  Designation

Trade names: EOS Aluminium AlSi10Mg (the dominant industrial powder); 3D Systems LaserForm AlSi10Mg; SLM Solutions AlSi10Mg; Renishaw AlSi10Mg-0407. The cast equivalent is EN AC-43000 / ISO 3522 AlSi10Mg.

B.  Full Chemical Name

Hypoeutectic aluminium-silicon casting alloy with magnesium age-hardening addition. Composition (wt%): Si 9.0–11.0, Mg 0.2–0.45, Fe ≤ 0.55, Cu ≤ 0.05, Mn ≤ 0.45, Ni ≤ 0.05, Zn ≤ 0.10, Pb ≤ 0.05, Sn — , Ti ≤ 0.15, Al — balance. Powder is gas-atomised; typical particle size 20–63 µm with a target d50 ≈ 35 µm.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Al(balance) — Si(9–11%) — Mg(0.2–0.45%) — Fe(≤ 0.55%) — Mn(≤ 0.45%) — Ti(≤ 0.15%) — minor (Cu, Ni, Zn, Pb < 0.10% each). Strengthening phases on aging: β'' / β' Mg₂Si needles in α-Al matrix.

Fig. 1.  Repeating unit / structural schematic of the polymer matrix.

Fig. 2.  Schematic of the single-phase polymer (no reinforcement).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF ALSI10MG (EOS ALUMINIUM ALSI10MG) (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XY BUILD DIRECTION (HORIZONTAL)

In the XY orientation the tensile load is applied parallel to the powder-bed plane (in-plane). For polymer SLS this is typically the stronger orientation due to better neck formation between particles within a single layer; for metal DMLS/SLM, columnar β / α-grain growth perpendicular to the build direction also yields different anisotropy that is partially relieved by post-build heat treatment (e.g. stress-relief, HIP).

TABLE II
 MECHANICAL PROPERTIES — XY ORIENTATION (ALSI10MG (EOS ALUMINIUM ALSI10MG))

IV.  MECHANICAL PROPERTIES — Z BUILD DIRECTION (VERTICAL)

In the Z orientation the tensile load is applied perpendicular to the powder layers; failure occurs across inter-layer fusion bonds. For polymer SLS the Z properties are typically 70–90 % of XY; for metal LPBF (laser powder-bed fusion) processes Z elongation is often higher due to the columnar grain structure but UTS / yield can be slightly lower in the as-built state. Heat treatment (anneal, HIP) reduces the anisotropy substantially.

TABLE III
 MECHANICAL PROPERTIES — Z ORIENTATION (ALSI10MG (EOS ALUMINIUM ALSI10MG))

AlSi10Mg DMLS exhibits modest as-built anisotropy: UTS is nearly isotropic but Z-direction yield and modulus are 10–15 % lower than XY due to columnar prior-α grains aligned along the build direction and residual inter-layer microporosity. Stress relief (270 °C / 90 min) reduces anisotropy substantially; T6 (solution-treat 510 °C / age 160 °C) yields essentially isotropic properties at the cost of ~20 % UTS reduction in exchange for ~50 % elongation increase.

V.  RECOMMENDED PROCESS PARAMETERS

Values summarised below give consensus operating windows from public datasheets (EOS, 3D Systems, BASF Forward AM, SLM Solutions). Specific machines and parameter sets may differ within ±10 %; the supplier's verified parameter sheet always supersedes this table.

TABLE IV
 RECOMMENDED LASER POWDER-BED-FUSION PROCESS PARAMETERS FOR ALSI10MG (EOS ALUMINIUM ALSI10MG)

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: Not applicable (metallic alloy).

Metals do not exhibit a glass transition. The closest analogue is the eutectic temperature (~577 °C for Al-Si) and the alloy's solidus / liquidus range (560–620 °C for AlSi10Mg). Continuous service temperature is governed by creep and over-aging — typically ≤ 175 °C for parts under load.

VII.  HEAT DEFLECTION TEMPERATURE (HDT)

Heat deflection temperature is the temperature at which a standard bar deflects 0.25 mm under a specified flexural load (ASTM D648 / ISO 75).

TABLE V
 HEAT DEFLECTION TEMPERATURE OF ALSI10MG (EOS ALUMINIUM ALSI10MG) UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Lightweight high-conductivity alloy

Density 2.67 g/cm³ (vs 7.85 for steel, 4.43 for Ti-6Al-4V), thermal conductivity 103–119 W/m·K (vs ~16 W/m·K for stainless steel). Combined with the part-consolidation freedom of AM, AlSi10Mg has rapidly displaced machined aluminium for heat-exchangers, heat-sinks, and high-frequency RF housings where mass and thermal budgets matter.

B.  Near-cast-T6 mechanical performance — as built

Laser rapid solidification (cooling rates ~10⁵-10⁶ K/s) yields a fine cellular Al-Si eutectic microstructure that approximates the dispersed-strengthening of T6-treated cast AlSi10Mg. As-built UTS ≈ 460 MPa exceeds many wrought 6000-series aluminiums and approaches 7000-series strength at half the alloying complexity.

C.  Heat treatment to tune properties

Stress relief at 270 °C / 90 min preserves as-built strength while reducing residual stress; T6 (solution treatment at 510 °C followed by age at 160 °C) homogenises microstructure, drops UTS to ~340 MPa, but doubles elongation to ~10–15 %. T6 is preferred when the part will be machined or fatigue-loaded; stress-relief is preferred when peak strength is paramount.

D.  Anisotropy — modest, controllable by heat treatment

As-built AlSi10Mg has ~10–15 % anisotropy in yield strength between XY and Z, attributable to columnar α-Al grains. Hot Isostatic Pressing (HIP) at 520 °C / 100 MPa / 2 h closes residual microporosity and yields essentially isotropic properties, recommended for fatigue-critical aerospace parts.

E.  Weldability and machinability

AlSi10Mg DMLS parts can be conventionally machined, wire-EDM-cut, and TIG-welded using AlSi5 filler. Surface finish in the as-built condition is Ra ~6–10 µm (rough); polished or shot-peened surfaces achieve Ra < 1.5 µm and improve fatigue life by ~30 %.

IX.  REPRESENTATIVE APPLICATIONS

AlSi10Mg (EOS Aluminium AlSi10Mg) is typically deployed in the following applications:

1)  Heat exchangers and cold plates: Lattice / micro-channel heat-sinks for power electronics, aerospace ECS (environmental control systems), and HPC liquid cooling — exploiting AM's geometric freedom to triple surface area vs machined alternatives.

2)  Lightweight aerospace brackets: Mass-optimised brackets for satellites and aircraft — topology optimisation typically delivers 30–50 % mass reduction vs machined Al alternatives at equivalent stiffness.

3)  Automotive intake manifolds and pump impellers: Internal-combustion air intake manifolds (consolidating multi-piece welded assemblies into single AM parts), water-pump impellers, and turbocharger compressor housings.

4)  RF and antenna housings: Conformal antenna housings, 5G base-station heat-sink-housings, and waveguide components — the metal AM process yields good electrical conductivity (~70 % IACS) and dimensional precision.

5)  Tooling inserts with conformal cooling: Injection-mould inserts with internal cooling channels following the part geometry — cycle-time reductions of 20–40 % are typical because AM enables true conformal cooling.

X.  REFERENCES

[1]  EOS GmbH, “EOS Aluminium AlSi10Mg — Material data sheet,” EOS Metal Solutions, 2018. [Online]. Available: https://uploads-ssl.webflow.com/5f2de60d3f802f48bd2d6305/5f51ae05d2f83f2899486b73_eos_alsi10mg_9011-0024_m290_material_data_sheet_flexline_07-18_en.pdf

[2]  EOS GmbH, “Material data sheet EOS Aluminium AlSi10Mg,” Fathom Manufacturing reprint. [Online]. Available: https://fathommfg.com/wp-content/uploads/2020/11/EOS_Aluminium_AlSi10Mg_en.pdf

[3]  Forge Labs, “Aluminum AlSi10Mg — Lightweight High-Performance Alloy,” Material reference. [Online]. Available: https://forgelabs.com/3d-printing/materials/aluminum-aisi10mg

[4]  K. Kempen et al., “Mechanical properties of AlSi10Mg produced by Selective Laser Melting,” Physics Procedia, vol. 39, pp. 439–446, 2012.

[5]  S. Romano et al., “Fatigue behavior and mean stress effect of as-built and surface-machined AlSi10Mg specimens produced by SLM,” Int. J. Fatigue, vol. 117, pp. 47–62, 2018.

[6]  ISO 6892-1:2019, “Metallic materials — Tensile testing — Part 1: Method of test at room temperature,” ISO, 2019.

[7]  ASTM E8/E8M-22, “Standard Test Methods for Tension Testing of Metallic Materials,” ASTM International, 2022.

[8]  ASTM F3001-14, “Standard Specification for Additive Manufacturing Titanium-6 Aluminum-4 Vanadium ELI (Extra Low Interstitial) with Powder Bed Fusion,” ASTM International, 2014.

[9]  ASTM F3122-14, “Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes,” ASTM International, 2014.

[10]  ASTM F3055-14a, “Standard Specification for Additive Manufacturing Nickel Alloy (UNS N07718) with Powder Bed Fusion,” ASTM International, 2014.

[11]  ISO 3369:2006, “Impermeable sintered metal materials and hardmetals — Determination of density,” ISO, 2006.

[12]  EN AC-43000, “Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties,” CEN, current edition.

(Image Source : Forgelabs)