Machine Design

New Superalloys Boost Direct Metal Laser Sintering

EOS GmbH – Electro Optical Systems

Often used in the additive building of prototypes, direct-metal laser sintering (DMLS) also works well in rapid manufacturing across a range of industries. This trend is supported by current advances in materials. For example, EOS GmbH – Electro Optical Systems, Munich, Germany, recently developed nickel superalloy EOS IN718 and aluminum alloy EOS AlSi10Mg. EOS IN718 is similar to Inconel 718, has excellent mechanical strength, and withstands high temperatures. The alloy provides good tensile, fatigue, creep, and rupture strength up to 1,292°F. Its excellent corrosion resistance makes the alloy suitable for parts ranging from fasteners and valves to aerospace gas turbines.

Inconel 718 has long been used for these kinds of components, but laser-sintered IN718 can provide a simpler solution because it eliminates machining. This is important because nickel alloys can be difficult to cut on a traditional machine tool.

IN718 can be heat treated following the same AMS 5662 and AMS 5664 standards that apply to Inconel alloys. Secondary operations that can be performed on DMLS parts include machining, spark-eroding, micro shot-peening, polishing, and coating.

Other nickel-based superalloys in the company’s pipeline for the future include EOS IN625, which is similar to Inconel 625.

EOS AlSi10Mg, on the other hand, contains aluminum, magnesium, and 9 to11% silicon to increase the material’s strength and hardness. It has properties similar to those of the traditional casting alloy. In both conventional and laser-sintered forms, the alloy retains aluminum’s light weight and high thermal conductivity. The additional elements give AlSi10Mg good casting properties, such as higher melt fluidity.

In its conventional form, AlSi10Mg often casts thin-walled, intricate parts. The laser-sintered form lets users build more-complex, lightweight parts with even thinner walls. Because DMLS rapidly solidifies parts, laser-sintered components have similar properties to conventional cast parts after T6 heat treatment. The laser-sintered parts can withstand secondary operations with EDM, welding, coating, polishing, wire eroding, and microblasting. Applications for the alloy include lightweight, load-bearing parts in motorsports, aerospace, and pneumatics.

© 2010 Penton Media, Inc.

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