October_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 0 1 9 A dditive manufacturing (AM) re- quires an interdisciplinary mind- set. Design, materials, application objectives, and manufacturing technolo- gies all play a role in the successful pro- duction and lifetime performance of 3D-printed parts. The design freedom made possible by AM can only be fully re- alizedwhen the optimummaterial is cho- sen to execute the intended design—and the material will only perform at its best in a 3D printer that is up to the challenges the design itself presents. Metal powder quality is generally no longer an issue, provided the pow- der comes from a reputable supplier. It is also recommended that multiple sources in the material supply chain be identified. Materials engineers have fine-tuned the methodologies with which existing metal alloys are com- monly prepared for 3D printing via gas or plasma atomization of either wire or bar metal stock. In addition, the pric- es of many widely used powders have been coming down in recent years. Nu- merous time-tested, certified materials, once properly powdered, can now be printed. At the same time, superalloys created specifically for AM are becom- ing more available, delivering the exact- ing characteristics a particular industry requires for optimum part production. The ability of AM to deliver previ- ously impossible geometries with intri- cate internal structures is sparking the imaginations of engineers across many industries. Replacement parts can also be printed without the need to rede- sign for 3D printing. Whatever the goal, application requirements will always be the starting point when considering which material to use. Beginning with weldability (because AM is essential- ly a micro-welding process), these can include lighter weight, strength and rigidity, temperature range, thermal conductivity, and/or anodizability. AM system manufacturers often work di- rectly with users to create appropriate manufacturing process parameters for each chosen material. Titanium and aluminum alloys, along with Inconel and Hastelloy X su- peralloys, are some of the materi- al blends currently in demand for 3D printing of mission-critical, regulatory approved, and extreme environment applications. How does one decide which material to use? Ask the design engineers who are driven by application requirements. As the industry examples below demonstrate, each of these ma- terials brings with it a spectrum of qual- ities that best suit specific performance parameters. CASE STUDIES Inconel 718— Hanwha Power Sys- tems is developing turbomachinery for a high-efficiency power generation sys- temwith solar energy as its heat source. Both temperature and pressure in such a system need to be very high, so the company designed a shrouded impeller in which the flow path of the working fluid is covered on both top and bottom (Fig. 1a). While the nickel alloy Inconel 718 offered the high-temperature qualities METAL ADDITIVE MANUFACTURING: CONSIDERING THE RELATIONSHIP BETWEEN ALLOY AND APPLICATION Case studies from a range of industries illustrate how advanced additive manufacturing capabilities optimize both material performance and value. TECHNICAL SPOTLIGHT Fig. 1 — (a) Most of today’s 3D printers would require a large amount of support structures (in red) to produce the Hanwha impeller design, while (b) a next-generation printer can manufacture the same design with minimal supports (in blue). (a) (b)