Progress in Additive Manufacturing

Additive manufacturing (AM) is among the fastest growing and most talked about manufacturing technologies on the planet. It is providing diverse opportunities for new product design and manufacturing. At GE, efforts such as the additively produced LEAP engine fuel nozzle and low-pressure turbine blade manufacturing are examples of how GE Aviation is leveraging these technologies in innovative ways. These are just a few illustrations of how AM is changing the manufacturing landscape and many others are described in the articles that follow. This rapid growth and investment poses several questions for the minerals, metals, and materials community: What exactly is ‘‘additive manufacturing?’’ Why has it captured the manufacturing industry imagination? How can the TMS community of materials and process technologists and leaders contribute to its growth and implementation? At its core, AM is a suite of technologies that ‘‘build’’ components using digital model data. The ASTM Committee F42 on AM Technologies has defined seven different process routes as being part of the field of AM. Each process has its own unique benefits and challenges that derive from the thermal and chemical processing cycle and the resulting microstructure. Any discussion of the technology needs to take into account the details of the resulting materials microstructure, surface roughness, and ability to maintain engineering tolerances, as well as implementation details about reliability and cost, and potential supply chain issues. The industrial excitement around this suite of processes is being driven by its capacity for empowering designers to focus on designing components for functionality rather than limitations of conventional processes such as casting, brazing, or forming processes. Furthermore, it is now enabling a whole new paradigm of rapid testing and product introduction wherein functional metal prototypes can be used for testing of individual components and manufacturing assembly processes (e.g., joining, forming, or machining). Using AM means product development cycles do not have to rely on traditional methods for manufacturing metallic prototypes, which can take months to produce. This leads to the key question: How can the minerals, metals, and materials community contribute to responsible, accelerated growth given the context of where the field is today? The key to industrial implementation for manufacturing technologies is a thorough understanding of the synergistic interaction of materials and processes. For AM, there are currently only a handful of materials and processes that are well understood, such as the previously mentioned laser powder-bed fusion of cobalt chrome and electron beam powder-bed fusion of titanium aluminide. To realize the full potential of AM, further maturation of the processing-structure-properties linkages will be required in a broader set of metal alloys and for many more processing approaches. When that happens, AM adoption will accelerate as industrial designers become empowered to select tailored material and process combinations that drive performance improvement for demanding applications. This special topic, Progress in AM, strives to meet that challenge by presenting a collection of articles that cover a broad spectrum of material systems and AM processing approaches including original research topics and application reviews. To download any of the articles, follow the URL: http://link.spring er.com/journal/11837/67/3/page/1 to the table of contents page for the March 2015 issue (Vol. 67, No. 3). In ‘‘Metallurgical and Mechanical Evaluation of 4340 Steel Produced by Direct Metal Laser Sintering,’’ by Elias Jelis, Matthew Clemente, Stacey Kerwien, Nuggehalli M. Ravindra, and Michael R. Hespos, the authors present new work on the Edward D. Herderick is the guest editor for the Process Technology and Modeling Committee of the TMS Materials Processing & Manufacturing Division, and coordinator of the topic Progress in Additive Manufacturing in this issue. JOM, Vol. 67, No. 3, 2015