Aluminium AlSi7Mg Powder

Aluminium AlSi7Mg powder is an aluminium alloy powder containing silicon and magnesium as its major alloying elements. This advanced engineering material offers exceptional strength, weldability and corrosion resistance along with excellent thermal properties.

AlSi7Mg powder has emerged as a versatile material for metal additive manufacturing processes like selective laser melting (SLM) and direct metal laser sintering (DMLS). Its unique composition imparts superior mechanical characteristics and makes it suitable for lightweight structural components across aviation, aerospace and automotive sectors.

Types of Aluminium AlSi7Mg Powder

AlSi7Mg alloy powder is available in different size distributions based on the metal AM process requirements:

Type	Particle Size Range
Fine grade	15 – 45 microns
Medium grade	45 – 105 microns
Coarse grade	105 – 150 microns

The finer powder particles have higher surface area and improve powder bed density as well as resolution of printed parts. However, they tend to be more reactive and require inert gas handling.

Coarser particles on the other hand enhance powder flow and reduce safety risks. But they provide lower resolution and accuracy for complex 3D printed components.

Composition of AlSi7Mg

The nominal composition of aluminium AlSi7Mg alloy powder is:

Element	Composition Range
Aluminium (Al)	Balance
Silicon (Si)	6.5 – 7.5 wt%
Magnesium (Mg)	0.45 – 0.55 wt%
Iron (Fe)	0.55 wt% max
Copper (Cu)	0.05 wt% max
Manganese (Mn)	0.45 wt% max
Zinc (Zn)	0.10 wt% max
Titanium (Ti)	0.15 wt% max

The high silicon and magnesium content in this aluminium powder alloy generates fine precipitates during solidification. This imparts significant strengthening through precipitation hardening mechanisms..

Key Properties of AlSi7Mg Powder

AlSi7Mg has a unique combination of material characteristics that makes it well-suited to additive manufacturing:

Property	Value
Density	2.68 g/cc
Melting Point	575 – 585 deg C
Thermal Conductivity	150 – 180 W/m-K
Thermal Expansion	21 – 24 x 10-6 /K
Modulus of Elasticity	72 – 77 GPa
Tensile Strength	430 – 490 MPa
Elongation at Break	8 – 10%
Hardness Brinell	95 – 110
High Temperature Stability	Excellent
Corrosion Resistance	Very Good

Some of the key advantages of AlSi7Mg powder include:

• High strength-to-weight ratio
• Dimensional stability at elevated temperatures
• Extremely smooth surface finish of printed parts
• Excellent corrosion resistance especially in marine atmospheres
• Easy post-processing and good machinability
• Superior weldability compared to other aluminium grades

Applications of AlSi7Mg Powder

The versatile material properties of AlSi7Mg enables usage across various sectors:

Industry	Applications
Aerospace	Structural brackets, engine components, complex lattices
Aviation	Airframe components, ducts, conduits
Automotive	Chassis parts, hubs, impellers
Marine	Deck hardware, antenna mounts, boat hulls
Industrial	Heat exchangers, process equipment
Consumer	Electronics housings, mods, accessories

AlSi7Mg’s exceptional strength-to-weight ratio combined with excellent dimensional accuracy of metal 3D printing unlocks lighter weight design optimization across transport applications.

Specifications for AlSi7Mg Powder

AlSi7Mg powder for additive manufacturing processes must conform to strict quality benchmarks.

Parameter	Requirements
Particle shape	Spherical morphology + satellites permitted
Particle size distribution	D10 > 10 microns; D90 < 100 microns
Apparent density	> 60% of solid density
Flow rate	> 15 s / 50 g
Moisture content	< 0.1 wt%
Oxygen content	< 0.5 wt%
Nitrogen content	< 0.5 wt%
Hydrogen content	< 0.2 wt%

Manufacturers aim to maximize powder recyclability and minimize variation in these metrics through stringent quality control frameworks.

Global Suppliers of AlSi7Mg Powder

Some of the leading global suppliers of AlSi7Mg alloy powder include:

Company	Brand Names	Particle Sizes Available	Price Range
Sandvik	Osprey + Ampal	15-45 um | 45-105 um	$90 – $110 per kg
Carpenter	ALSi7Mg	15-53 um | 53-150 um	$80 – $100 per kg
LPW Technology	LPW AlSi7Mg	15-45 um	$100 – $140 per kg
TLS Technik	AlSi7Mg04	10-45 um | 45-106 um	$75 – $90 per kg
AMC Powders	AlSi7Mg SLM	10-45 um	$70 – $100 per kg

Pricing varies based on order volume, lot size, regional distributors and customization options.

How AlSi7Mg Compares to AlSi10Mg for Metal AM

AlSi10Mg is another popular aluminium alloy used in powder bed fusion processes:

	AlSi7Mg	AlSi10Mg
Silicon content	6.5 – 7.5 wt%	9 – 11 wt%
Density	2.68 g/cc	2.67 g/cc
Tensile strength	430 – 490 MPa	400 – 460 MPa
Ductility	Higher	Lower
Weldability	Excellent	Moderate
Surface finish	Smoother	Rougher
Cost	Higher	Lower

While AlSi10Mg offers better affordability and printability, AlSi7Mg provides superior mechanical performance, corrosion resistance and post-processing characteristics.

Advantages and Limitations of AlSi7Mg

Some of the major advantages of AlSi7Mg powder include:

Advantages:

• Excellent strength-to-weight ratio for lightweighting
• High hardness plus good ductility
• Outstanding corrosion resistance
• Excellent thermal stability at higher temperatures
• Smoother surface finish than AlSi10Mg
• Better weldability than other Al-alloys

Limitations:

• Higher cost compared to AlSi10Mg powder
• Lower maximum operating temperature than aluminum alloys with higher Si content
• Reactivity with atmospheric moisture and oxygen requires careful handling
• Lower thermal conductivity than pure aluminum and copper alloys
• More supports required during printing due to lower printability

Recent Research Advancements with AlSi7Mg

Ongoing research on AlSi7Mg powder focuses on:

• Grain refinement through novel alloy compositions and heat treatment to attain ultra-fine microstructures leading to substantial improvements in yield strength, tensile strength and fatigue life
• Surface enhancement via advanced finishing techniques like abrasive flow machining, laser polishing and electro-polishing to minimize porosity-driven vulnerabilities and enhance functional performance
• Joining technologies including friction stir welding and other solid-state processes to enable integration, repair and modification of additively manufactured AlSi7Mg components for extended service life
• qualification and certification through extensive materials testing and process characterization following industrial standards to evolve specification frameworks for reliable end-use across mission-critical systems

Many OEMs are collaborating directly with AlSi7Mg powder vendors to push custom formulations tailored for their specific applications. The focus areas span building predictive capabilities around microstructure evolution, thermal behavior, defect mitigation, anisotropy quantification and industrial-scale quality assurance.

These sustained efforts will expand the high-performance envelope for metal additive manufacturing using AlSi7Mg alloy and proliferate its adoption across multiple sectors.

FAQ

Question	Answer
Is AlSi7Mg precipitation hardenable?	Yes, AlSi7Mg can be precipitation hardened through appropriate heat treatment to attain peak strength.
Why is AlSi7Mg preferred over AlSi10Mg in certain applications?	AlSi7Mg provides better mechanical properties like tensile strength and hardness along with superior corrosion resistance and weldability over AlSi10Mg.
What is the typical surface roughness achieved with AlSi7Mg AM parts?	AlSi7Mg printed parts demonstrate exceptional surface finish with average roughness (Ra) values ranging from 5 – 15 microns.
What are some alternatives to AlSi7Mg powder?	Alternate options include AlSi10Mg, AlSi12, Scalmalloy, aluminum 6061 alloy, titanium Ti64 amongst others.
What is the typical tolerance level for AlSi7Mg AM components?	Dimensional tolerances upto +/- 0.3% are routinely achieved for AlSi7Mg printed parts based on optimized parameters and geometric complexity.
What types of post-processing are commonly used on AlSi7Mg AM parts?	Typical post-processing includes – Support removal > Heat treatment > Surface enhancement – grinding/polishing > Quality inspection.