A Guide to Metal Powders for Additive Manufacturing

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A Guide to Metal Powders for Additive Manufacturing
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The use of additive manufacturing (AM) has become increasingly widespread in the production of items made from materials like metals, ceramics, and polymers. However, metal additive manufacturing (MAM) has been shown to have the most significant impact across different industries.

Nowadays, metal powder can be melted, fused, or joined layer upon layer to create various items using computer-aided design (CAD) software. Some of the most common metal powders used include:

  • Stainless steel
  • Titanium
  • Aluminum
  • Copper

In the aerospace industry, the number of parts needed to assemble the heat exchanger in the GE9X engine for the Boeing 777X has been significantly reduced with MAM. The total number of parts was reduced from 300 separate parts to one single component with the use of metal powders.

Furthermore, the heat exchanger for this powerful aircraft engine is about three-quarters less expensive and 40% lighter than its predecessor, the GE90.

In construction, metal was used to create the first bridge with AM techniques. The bridge spans the width of a canal in Amsterdam, Netherlands. Various AM production processes across different industries including bicycle frames for sports have been explored.

In this article, we’ll discuss different metal powders and how they can be used in AM to improve manufacturing in different industries.

Stainless Steel

When used in AM, stainless steel has been shown to have effective mechanical properties such as strength, hardness, formability, and resistance to impact. Stainless steel is used in electron beam melting (EBM) to produce robust components that are used in severe conditions like rockets and jet engines. EBM is an AM technique that uses an electron gun controlled by a computer to create completely dense, three-dimensional objects from metal powder.

Titanium Powder

Titanium is used in various additive manufacturing processes to create parts for industries such as the aerospace and medical sectors. Available in four separate grades, unalloyed titanium has a high level of resistance to corrosion. It’s also malleable, making it suitable for the production of different forms and designs. The following are distinctive characteristics of each grade of pure, unalloyed titanium:

  • Grade 1: The softest, most malleable titanium with a high corrosion resistance, grade 1 is often used in marine and chemical applications.
  • Grade 2: A metal with a low density, grade 2 is commonly used in industrial applications such as pressure containers, aeronautics, heat exchangers, and equipment used in the processing of chemicals.
  • Grade 3: A stronger and less formable titanium than grades 1 and 2, grade 3 is often used in industrial applications and the aerospace industry.
  • Grade 4: A less ductile titanium than grades 1 to 3, grade 4 is a high-strength metal, making it well-suited to industrial, aerospace, and medical applications.

Titanium alloys contain a blend of titanium and other elements. They’re used in AM to manufacture an extensive range of applications including surgical titanium implants, especially when there is a need for bone or tissue to have direct contact with metal.

Titanium alloy is also used for parts such as connecting rods and gearboxes in powerful race engines. In addition, industrial parts like discs, rings, fasteners, and blades are often created with titanium alloy.

Powdered Aluminum

Aluminum metal powder has a low weight, making it suitable for the production of automotive and racing components. When combined with other elements like magnesium or silicon, aluminum alloy can also be created. Aluminum powder can resist severe weather conditions, so it is often also used in the aerospace industry.

Boeing, for example, uses additive manufacturing techniques in the aerospace industry to produce custom-made aluminum parts for its helicopters, aircraft, and satellites. In the automotive industry, Porsche has created high-performance aluminum pistons in its 911 GT2 RS, allowing the engine to correlate accordingly with load conditions. This has optimized the piston structure, resulting in a reduction in the weight of each piston.

Copper Powder

A Guide to Metal Powders for Additive Manufacturing
Copper

The use of copper in additive manufacturing has become increasingly widespread in recent years. Copper is mainly used for thermal and electrical parts. In the past, conventional manufacturing techniques made it difficult to produce complex components that are used for these types of applications. The reason for this is that copper has a high level of optical reflectivity, making it difficult to produce intricate copper parts.

Fortunately, additive manufacturing techniques have made it possible to create complex designs that utilize the thermal and electrical performance produced by copper. As a result, manufacturers are now able to create parts for various products. For example, components for electric vehicles are now being produced with copper and laser powder bed fusion (LPBF). Another example is the production of cooling sockets for milling tools using fused filament fabrication (FFF).

Additive Manufacturing (AM) Will Continue to Grow

The use of metal powders in AM has grown significantly in recent times. The global market size is expected to increase by USD 7,574 million between 2022 and 2027. Many AM techniques are dependent on the use of premium-quality metal powders to create products for different industries such as aerospace, automotive, and architecture.

Although many AM technologies can use similar metals, it’s generally advisable to select the most suitable metal powder based on the product being manufactured.

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