Advanced Materials & Processes

NOV-DEC 2013

Covers developments in engineering materials selection, processing, fabrication, testing/characterization, materials engineering trends, and emerging technologies, industrial and consumer applications, as well as business and management trends

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Julie: That MGI is established and able to draw national attention to ICME and materials science and engineering in general is exciting. ICME is tremendously powerful. It is enabling materials science and engineering to participate in systems-level engineering practice for the design of new components and devices, and the optimization of processing and manufacturing for quality and affordability. It also underlies the performance/capability prediction required for real-time structural health monitoring. MGI will help to build the national infrastructure and public-private partnerships to support this critical integration of materials understanding with other engineering disciplines. Additive manufacturing: Holy Grail or hype? Diran: It is neither. It is a tsunami. We will see major advances in this area, not only in engineered aerospace and high integrity applications, but also in the field of prosthetics. The challenge will be the starting material. If the feed material is metal powder, the resultant properties will be influenced by the microstructure of the initial powder, and we cannot forget the oxides. Every powder particle has a high surface area to volume ratio, and the level of oxides being deposited will be significant. If the feed is a melt, flow properties will be paramount and much work is needed to control the flow properties of molten metal through microscopic jets. Jeff: For those of us who have been using additive manufacturing (AM) for several years, the answer is probably both. There is rarely a panacea for any sophisticated problem. AM is certainly moving from the realm of simple prototyping to development of exotic materials including biological applications. Practical issues such as surface finish and how to test products versus supply chain materials continue to confound established industries. Ultimately the market will decide if these novel manufacturing techniques will displace conventional manufacturing because it is then that full cycle costs will determine true value. Al: AM has real promise. After evolving over the past 20 years or so, it is now finding some very useful applications, beyond making one-off parts or simple prototypes. One example is in building titanium parts for aerospace. Rather than using subtractive processes that start with a desk-size chunk of titanium, additive processes can be used to make high-quality parts with very little waste. Titanium is one of the most forgiving materials, so it has worked nicely. More process discoveries are needed to work with other alloys as well. Because AM has gotten so good, so fast, over time it will begin to invade the turf of more traditional processes. Greg: While the scale of manufacturing will have natural limits, AM opens significant new possibilities in application of new topological optimization practices and novel graded structure options. The current limitation in metals is the application of a new process to old materials that were never intended to be formed as high- oxygen multipass weld deposits. The obvious opportunity is ICME design of new materials optimized for the process. Another hot topic is nanotechnology. Does nano have the potential to revolutionize materials engineering or is it simply another tool? Greg: The nanoscale is one of many scales in the interactive structural hierarchy of materials envisioned by Cyril Smith. It is however the "defining" length scale of ultrahigh-strength alloys. What's new in true nanotechnology is the level of predictive ICME control of nanodispersion strengthening in the design of precipitation-strengthened alloys. Al: In large measure, nanotechnology probably has already revolutionized materials engineering. It has been evolving over the past few decades under different names. Because nanoparticles have a large surface area per unit volume, interesting quantum effects occur on the surface. Because of this, noncatalytic materials can be made to behave as catalysts. This is very promising—the ability to turn routine, inexpensive materials into more exotic ones, such as using nickel as a catalyst in place of palladium. We can't do this on a mass scale yet. The material readiness level is still very low, and the manufacturing readiness level is even lower, but it's coming along. Jeff: I come from a research background in physical metallurgy in which we operated in the nanoscale regime before the name was invented. So I watched as the physicists and chemists rediscovered what we already knew about the importance of understanding materials behavior at the nanoscale. Today I believe that this attention has revealed new knowledge that would not have happened without a focus on this length scale. It is not the realization that nanoscale structure and phenomena are important to materials properties that is revolutionary, but rather it is the ability to image and manipulate materials at the nanoscale that makes for revolution. How can advances in MSE help address humanity's grand challenges? Greg: The great challenge of this century is the historic corruption enabled by extreme public/private collusion. Best known for undermining the global economy, it pervades all sectors, notably including the peculiar value system of our research universities. While digging out through reestablishment of a system of laws ADVANCED MATERIALS & PROCESSES • NOVEMBER-DECEMBER 2013 27

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