AlSi50 Powder

AlSi50 is an aluminum-silicon alloy powder containing 50% silicon and remainder aluminum. It offers an exceptional combination of properties like low density, high fluidity, low thermal expansion, high specific strength, and corrosion resistance.

AlSi50 Powder Composition

The typical composition of AlSi50 alloy powder is:

Element	Composition
Aluminum (Al)	Balance
Silicon (Si)	48-52%

• Aluminum forms the matrix providing ductility, toughness and corrosion resistance.
• Silicon increases hardness, fluidity and reduces the coefficient of thermal expansion.

The high 50% silicon content results in a eutectic composition with the lowest possible melting point and excellent castability. Strict control of the Al to Si ratio is critical.

Properties of AlSi50 Powder

AlSi50 powder possesses a unique mix of properties making it suitable for high performance applications:

Property	Value
Density	2.55 g/cm3
Melting Point	577°C
Ultimate Tensile Strength	200-300 MPa
Elongation	<1%
Hardness	100-120 HB
Thermal Conductivity	50-90 W/m-K
CTE	12-15 x 10<sup>-6</sup>/°C
Young’s Modulus	80-90 GPa
Corrosion Resistance	Excellent

• Low density – Up to 40% lower than titanium alloys and steels.
• High fluidity when molten – Enables excellent castability and mold filling.
• High strength-to-weight ratio – Specific strength comparable to titanium alloys.
• Low coefficient of thermal expansion – Dimensions remain stable over a wide temperature range.
• Excellent corrosion resistance – Protective oxide layer prevents corrosion in most environments.
• Good thermal conductivity – Twice that of titanium alloys allowing efficient heat dissipation.

This unique property profile makes AlSi50 suitable for applications where low mass, precision, stability, and strength are critical.

Applications of AlSi50 Powder

The key properties of AlSi50 powder make it ideal for:

Applications	Benefits
Automotive components	Low density and excellent castability.
Aerospace parts	High specific strength, stable dimensions.
Electronic substrates	Thermal management, CTE match with ceramics.
Mirror blanks	Low density, machinability, stability.
Medical implants	Biocompatible, non-toxic, corrosion resistant.

• Automotive – Used in pistons, engine blocks, drivetrain parts to reduce weight and improve fuel efficiency.
• Aerospace – Ideal for precision aerospace components like actuators and turbocharger wheels requiring highest strength-to-weight.
• Electronics – Substrates for PCBs, IC packages to manage thermal loads while matching expansion behavior of ceramics.
• Optics – Mirror blanks, telescopes benefit from high dimensional stability and machinability.
• Medical – Excellent biocompatibility and corrosion resistance for implants like orthopedic devices.

AlSi50 delivers maximum performance where low density, precision, and strength are critical.

AlSi50 Powder Specifications

AlSi50 powder is available in various size fractions, shapes, and purity levels:

Parameter	Options
Particle size	10 – 150 microns
Particle shape	Irregular, spherical
Apparent density	Up to 2.7 g/cm3
Flow rate	Up to 25 s/50g
Purity	Up to 99.7%
Alloy variants	AlSi40, AlSi30

• Smaller particles promote higher sintered density while large particles improve flowability.
• Spherical morphology enhances powder flow compared to irregular particles.
• Higher apparent density increases effective loading in composites manufacturing.
• Faster flow rates improve ease of powder handling and processing.
• High purity grades minimize contamination issues.
• Aluminum-silicon alloys with 30-40% silicon also available.

Powder attributes can be customized based on specific application requirements and processing methods.

Consolidation Methods for AlSi50 Powder

AlSi50 powder can be transformed into full density components using techniques like:

Method	Details
Additive manufacturing	Excellent geometric freedom for complex shapes.
Metal injection molding	High precision net shape capability.
Press and sinter	Economical for higher volume simpler shapes.
Casting	Leverages excellent fluidity and mold filling behavior.
Extrusion	For profiles, rods and tubes.

• Powder bed fusion AM techniques like selective laser melting are ideal for low volume complex parts.
• Metal injection molding offers closest tolerances and surface finish.
• Pressing followed by liquid phase sintering is commonly used but secondary processing needed.
• Investment casting provides higher productivity for simpler geometries.
• Extrusion is suitable for continuous production of bars, rods and tubes.

The consolidation method strongly influences final properties, microstructure and cost economics.

Heat Treatment of AlSi50 Parts

The following heat treatments can be used to modify AlSi50 properties:

Heat Treatment	Details	Purpose
Solution heat treatment	500-550°C, quench	Dissolve soluble phases
Artificial aging	150-180°C, 5-10 hrs	Precipitation hardening
Stress relieving	250°C, 2 hrs	Remove residual stresses

• Solution treatment dissolves silicon particles in the aluminum matrix followed by rapid cooling.
• Subsequent aging causes silicon to re-precipitate as fine dispersoids imparting strengthening.
• Low temperature stress relieving helps reduce residual stresses from prior shaping steps.

Proper heat treatment allows customizing the strength, hardness and ductility as per application requirements.

Comparison of AlSi50 Powder with Alternatives

Here is how AlSi50 compares to other eutectic aluminum-silicon alloys:

Alloy	AlSi50	AlSi40	AlSi30
Fluidity	Highest	High	Medium
Castability	Excellent	Very Good	Good
Hardness	High	Medium	Low
Strength	High	Medium	Low
Thermal Conductivity	Medium	High	Highest
CTE	Low	Medium	High
Cost	High	Medium	Low

• AlSi40 offers the best all-round combination of fluidity, strength and thermal conductivity.
• AlSi30 provides highest thermal conductivity but lowest strength and fluidity.
• AlSi50 has the highest fluidity, hardness and strength but lower thermal conductivity.

AlSi50 is preferred where maximum castability, dimensional stability, and high specific strength are critical.

AlSi50 Powder Manufacturers

As a specialty alloy powder, AlSi50 is produced by a range of suppliers globally:

Manufacturer	Country
Binder Metals	Germany
CNPC Powder	China
Sandvik Osprey	UK
Rio Tinto Metal Powders	Canada
Valimet Inc	USA
ASK Chemicals	USA

Reputable manufacturers have stringent quality control and conform to international standards for composition, particle size distribution, apparent density and impurity levels.

AlSi50 Powder Pricing

As an advanced specialty alloy powder, AlSi50 commands a premium price over plain aluminum grades:

Powder Grade	Particle Size	Price ($/kg)
For pressing	Under 150 μm	$15-25
For sintering	45-150 μm	$18-30
For AM	15-45 μm	$30-50
High purity	Up to 10 μm	$40-75

• Finer fractions for AM and sintering are costlier than coarse powder for pressing.
• Small lot sizes under 100 kg attract higher prices.
• High purity grades with lower oxygen and nitrogen content are 50-100% more expensive.
• Reducing silicon content to AlSi40 lowers cost by around 20%.

Volume discounts, longer term contracts and simpler particle specifications help lower cost.

Health and Safety Considerations for AlSi50 Powder

Like any metal powder, AlSi50 powder requires safe handling:

Hazard	Precautions	PPE
Skin/eye contact	Avoid direct contact. Rinse if exposed.	Gloves, goggles
Inhalation	Avoid breathing dust. Ensure ventilation.	Respirator
Ingestion	Avoid hand-mouth transfer. Wash hands.	–
Fire	Use sand. Do not use water.	Protective gear

• Wear gloves, goggles, mask when handling powder.
• Avoid skin contact. Wash after exposure.
• Store in cool, dry place away from sparks, flames.
• Ensure proper ventilation and dust collection.
• Refer SDS and local regulations for complete guidelines.

With proper precautions and PPE, AlSi50 powder can be safely handled.

Inspection and Testing of AlSi50 Powder

To ensure quality specifications are met, AlSi50 powder should undergo:

Parameter	Method	Specification
Chemical composition	OES, XRF, wet chemistry	Conformance to Al and Si content
Particle size distribution	Laser diffraction, sieving	D10, D50, D90 within range
Powder morphology	SEM imaging	Shape and flow characteristics
Apparent density	Hall flowmeter test	Minimum specified density
Flow rate	Hall flowmeter test	Maximum seconds for 50g flow
Impurity levels	ICP or LECO analysis	Low oxygen, moisture content

Testing should be done periodically as per ASTM standards to ensure consistency in production quality and performance in end-use applications.

FAQs

Q. What is AlSi50 used for?

A. AlSi50 is ideal for applications like automotive components, aerospace parts, and electronic substrates where low mass, dimensional stability, and high fluidity are critical.

Q. Does AlSi50 require heat treatment?

A. Optional heat treatment including solutionizing and aging can be done to enhance strength by precipitating silicon particles in the microstructure.

Q. What methods can consolidate AlSi50 powder?

A. AlSi50 powder can be consolidated to full density using metal injection molding, casting, additive manufacturing via SLM/EBM, extrusion, and sintering.

Q. Is AlSi50 readily weldable?

A. AlSi50 has relatively poor weldability owing to high silicon content. Special filler material and techniques are required for welding this alloy.

Q. Is AlSi50 powder safe to handle?

A. Like any fine metal powder, standard safety precautions must be taken when handling AlSi50 powder to minimize health and safety risks.