Aluminium AlSi12 Powder

Overview of Aluminium AlSi12 Powder

Aluminium AlSi12 powder is an aluminium alloy powder containing 12% silicon as its major alloying element. It is known for its excellent fluidity, low melting point, and good corrosion resistance. This guide provides detailed information on AlSi12 powder metallurgy, its composition, properties, production methods, applications, and suppliers.

AlSi12 Powder Key Properties:

• Composition: Aluminium with 12% Si
• Melting point: Around 575°C
• Density: 2.68 g/cm3
• Excellent fluidity and castability
• Good corrosion resistance
• Low coefficient of thermal expansion
• High strength-to-weight ratio

AlSi12 Powder Composition

The table below shows the typical chemical composition of aluminium AlSi12 alloy powder:

The precise silicon content determines the alloy designation – AlSi12 contains between 11-13% silicon by weight. The remaining is aluminium making up the base. Other elements like iron, manganese, and magnesium are present only in trace quantities as impurities.

Why is silicon added to aluminium?

Silicon is strategically added to create an aluminium silicon alloy offering unique benefits:

• It lowers the melting point of pure aluminum for better castability and fluidity in molten state
• Improves strength, hardness and wear resistance
• Enhances corrosion resistance properties
• Alters coefficient of thermal expansion

Controlling silicon percentage allows customizing alloy properties for different applications during aluminium powder metallurgy.

Manufacturing Process of AlSi12 Powder

AlSi12 alloy powder is manufactured using the following standard metal powder processing techniques:

1. Gas Atomization

• Aluminium ingots are induction melted along with silicon
• The molten metal stream is disintegrated using compressed air or inert gas jets
• This leads to rapid solidification of fine droplets into powder
• Powder particle size and morphology can be controlled by process parameters

2. Water Atomization

• Similar to gas atomization, but molten metal stream is broken up by high-pressure water jets
• Leads to faster cooling and finer powders

3. Mechanical Milling

• Ball milling of aluminium and silicon metal powder mixes
• Leads to particle refinement and alloying by cold welding and fracturing

Benefits: Gas and water atomization allow high purity, alloyed, spherical and reactive powders. Mechanical milling technique is simple and cost-effective. Both methods yield fine aluminium AlSi12 powders suitable for additive manufacturing and powder injection molding.

Properties of AlSi12 Alloy Powder

Aluminium silicon AlSi12 has well-balanced physical, thermal, electrical and mechanical properties making it suitable for lightweight engineering applications:

Physical Properties

Mechanical Properties

Electrical Conductivity

Around 30% IACS

Lower density versus pure aluminium allows lightweighting. Excellent fluidity allows casting complex shapes. High hardness and strength combined with low weight makes AlSi12 suitable for engineering and automotive components. Moderate corrosion resistance allows use in various industrial environments.

AlSi12 Powder Particle Size Distribution

Commonly available particle size distributions:

• D10 = 20-30 μm
• D50 = 35-45 μm
• D90 up to 100 μm

Powders are spherical in shape with satelliting. Different size distributions available based on application method.

Applications of Aluminium AlSi12 Powder

The major applications of AlSi12 alloy powder include:

Automotive Parts

AlSi12 is used to manufacture the following lightweight powder metallurgy automotive parts:

Aerospace Components

AlSi12 sees usage in aircraft and spacecraft components, e.g. impellers, turbines.

Industrial Parts

Heat sinks, electronic housings, mechanical seals, hydraulics, valves, tooling jigs etc.

Medical Devices

Low weight and biocompatibility allows usage for prosthetics and implants.

Advantages Driving Usage

The major factors promoting adoption of AlSi12 powder include:

• Lightweighting versus cast iron/steel parts
• Mechanically strong, wear and heat resistant
• Enables complex, net-shape powder metallurgy parts
• Cost-effectiveness
• Customization of alloy composition possible

The automotive sector is the biggest adopter of AlSi12 alloys for vehicle light-weighting.

AlSi12 Powder Fabrication Methods

AlSi12 alloy powder can be consolidated into end-use components using the following powder metallurgy techniques:

1. Metal Injection Molding (MIM)

• Mixing fine powder with binder into feedstock
• Molding using injection molding machine
• Debinding and sintering

Allows complex, high volume micro parts with net-shape capability.

Typical density achieved: ≥99% Dimensional accuracy: ±0.5%

Applications: Small intricate automotive and electronic parts like gears and locks.

2. Additive Manufacturing

• Direct metal printing using laser/e-beam based powder bed fusion
• No mold required
• Layer-by-layer selective melting and consolidation

Enables customized, rapidly prototyped parts with complex geometries.

Density: 90-95% Resolution: 50 μm vertically

Applications: Aerospace brackets, automotive prototypes, biomedical implants

3. Powder Forging

• Compacting of powder metal into preforms
• Hot forging preforms into high-density components

Suitable for automotive connecting rods and bearings.

Density achieved: ≥96% Production rate: High

4. Cold/Warm Compaction

Applications such as self-lubricating bearings with controlled porosity.

5. Aluminum Cylinder Bores

AlSi12 liners are made by centrifugal casting process into alloyed steel engine blocks for light-weight, fuel-efficient engines.

Standards and Specifications

Industrial grade AlSi12 alloy powder manufactured by reputed global suppliers conforms to the following specifications:

Customization

• Chemical composition tailored as per application requirements
• Particle size distribution adjusted based on production process needs

High purity medical grade powders specifically tested for biocompatibility are also available.