What is Metal Foam?
Metal foam is a celled structure made up of solid ligaments and permeable pores. This matrix of cells and ligaments is fully customizable and can be optimized to meet the performance requirements of a broad range of applications.
Metal foam, sometimes referred to as foamed metal, is commonly used in applications that benefit from a very high surface area and from the nature-mimicking morphology of the rigid cellular structure.
What is Reticulated (Open Cell) Foam?
Open Cell foam, also known as reticulated foam, features 100% open cells with a path through the foam in any direction for air or liquid.
The open cell nature allows liquids or gases to pass through but restricts flow to control flow rates and buffer pressure changes.
The high surface area to volume ratios offer heat transfer rates unattainable with any other material.
ERG builds a product called Duocel®; offered since 1967, Duocel® sets the standard of quality and uniformity among open cell foams.
What makes Duocel® Metal Foam unique?
Compared to other commercially available metal foams that often have closed cells and/or sintered or hollow ligaments, Duocel® offers unparalleled performance for applications involving fluid flow, heat transfer, and structural integrity.
The pores within Duocel’s metal foam structure are fully reticulated, or open, such that fluid can flow throughout the foam and interact with the very high surface area of the solid metal ligaments. This is important for applications such as heat transfer and flow control, in which the foam helps facilitate a highly compact and efficient solution.
All of our foam is open cell, or reticulated metal foam. This allows for superior liquid flow and impact absorption for a variety of applications.
The high uniformity of Duocel® foam allows crush strength to be precisely controlled by altering density, and pore or ligament size; making it ideal for energy absorption applications as well as allowing for further customizability of the bulk structure.
The thickness of the solid metal ligaments (determined by relative density) can be designed to absorb a desired amount of kinetic energy through compression, which occurs at a relatively constant stress without rebound or bounce-back. The foam’s solid ligaments also maintain ductility when crushed, which allows for enables designs with increased surface area and fluid/heat transfer interactions.
Duocel® metal foam can be machined to complex shapes, brazed, bonded, coated, and plated, making it extremely versatile from a manufacturability perspective. Metal foams can often simplify the manufacturing process when integrated into complex systems.
Our open cell metal foam can be made from many metal alloys including aluminum, copper, steel, Inconel, tin, gold, silver, and many others. The most popular Duocel metal foam is aluminum because of its excellent strength to weight ratio, conductivity, and compatibility with common system components.
Duocel® metal foams typically have the same metal purity as that of the parent alloy they are made from. Therefore, many familiar metal properties (such as chemical compatibility, conductivity, melting temperature, etc.) are transferrable to the foam’s unique form factor.
With high strength to weight ratio, our patented material offers solutions not available anywhere else.
What sizes does Metal Foam come in?
Duocel® foams are typically made in blocks up to approximately 16in x 16in x 4in (406mm x 406mm x 102mm) in size. Larger sizes are available by brazing multiple blocks together for larger requirements.
There are also limits to how small a foamed metal part can be, depending on PPI of the foam, because cutting the open celled structure too small or thin results in no connected ligaments. This table contains the standard minimum dimensions of uncompressed foam. Smaller dimensions and features are possible – please contact us to determine feasibility for your requirements.
Standard Minimum Dimension
Can foam be fabricated to a custom shape?
Yes. Much like a solid piece of metal, Duocel® metal foam can be machined to nearly any unique shape and dimension. Extra care must be taken for very small and tight-tolerance part features like small holes, sharp edges or small radii, precise angles, etc…
With so many metal foam uses, we have an in-house engineering team available for consultations regarding your specific project and size requirements.
*Example* Characteristics of Duocel® Metal Foam:
|Compression Strength||367 psi||(2.53 MPa)|
|Tensile Strength*||180 psi||(1.24 MPa)|
|Shear Strength*||190 psi||(1.31 MPa)|
|Modulus of Elasticity (Compression)*||15 × 103 psi||(103.08 MPa)|
|Modulus of Elasticity (Tension)*||14.6 × 103 psi||(101.84 MPa)|
|Shear Modulus||2.9 × 104 psi||(199.95 MPa)|
|Vickers Pyramid Number||35 HV|
|Bulk Thermal Conductivity||3.4 BTU/ft-hr-F|
|Coefficient of Thermal Expansion (0-100°C)||13.1 × 10-6 in/in–F||(23.58 × 10-6 m/m–C)|
|Corrosion Resistance||4.5 to 8.5 pH||Very Resistant|
- Solid Ligaments
- Open-celled, Permeable Pores
- High Strength to Weight Ratio
- High Surface Area to Volume Ratio
- Controlled Energy Absorption
- Versatile Manufacturability
- Can be Brazed and Soldered
- Can be Coated and Plated
- Standard Relative Density range: 4-12%
- Compressible to a factor of 6X+
- PPI Available: 5, 10, 20, 40
All of our materials are proudly 100% Made in the USA.