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The Youngstown, Ohio, based National Additive Manufacturing Innovation Institute (NAMII) hit the ground running and this week announced its first $4.5 million in awards for seven projects. Matching funds from proposal winners bring the value of the awards up to $5 million.
The Obama administration established NAMII in August 2012 as the pilot institute for the National Network for Manufacturing Innovation (NNMI) and President Obama brought the Youngstown institute to the nation’s attention when he mentioned it in January’s State of the Union address. The public-private-academic consortium comprises 40 companies, nine research universities, five community colleges, and 11 nonprofits. (Obama announced the NNMI concept just one year ago, in March 2012, and provided it with $45 million in federal funding from DOD, DOE, Department of Commerce, NSF, and NASA.)
According to the press release, all seven winning projects come from the ranks of NAMII consortium members and are R&D projects that address aspects of NAMII’s four thrust areas are technology development, technology transition, additive manufacturing enterprise, and education/workforce outreach.
Based on what I can see in the press release, none of these projects specify research on ceramic materials-the focus seems to be on polymers and metals. (I was not able to reach anyone at NAMII this morning.) NAMII says it will announce its second call for proposals in June at the RAPID 2013 Conference and Exposition in Pittsburgh, Pa. Let’s hope they add ceramic materials to the mix. We have often reported in CTT, additive manufacturing is an excellent fabrication technology for ceramics, as this example and this example show.
Here are the awards (from the press release).
“Maturation of Fused Depositing Modeling (FDM) Component Manufacturing“
Rapid Prototype + Manufacturing LLC (RP+M)
Led by small business part producer, RP+M, in partnership with equipment manufacturers and large industry system integrators and the University of Dayton Research Institute, this project will provide the community with a deeper understanding of the properties and opportunities of the high-temperature polymer, ULTEMTM 9085. Some of the key outcomes from this project include a design guide; critical materials and processing data; and machine, material, part and process certification.
“Qualification of Additive Manufacturing Processes and Procedures for Repurposing and Rejuvenation of Tooling“
Case Western Reserve University
Led by Case Western Reserve University, in partnership with several additive manufacturers, die casters, computer modelers, and the North American Die Casting Association, this project will develop, evaluate, and qualify methods for repairing and repurposing tools and dies. Die casting tools are very expensive—sometimes exceeding $1 million each—and require long lead times to manufacture. The ability to repair and repurpose tools and dies can save energy and costs, and reduce lead time by extending tool life through use of the additive manufacturing techniques developed by this team.
“Sparse-Build Rapid Tooling by Fused Depositing Modeling (FDM) for Composite Manufacturing and Hydroforming“
Missouri University of Science and Technology
“Fused Depositing Modeling (FDM) for Complex Composites Tooling“
Northrop Grumman Aerospace Systems
Two projects focusing on fused depositing modeling are to be co-led developed in close collaboration by Missouri University of Science and Technology and Northrop Grumman Aerospace Systems, in partnership with other small and large companies and the Robert C. Byrd Institute’s Composite Center of Excellence. These projects address a key near-term opportunity for additive manufacturing: the ability to rapidly and cost-effectively produce tooling for composite manufacturing. Polymer composite tools often involve expensive, complex machined, metallic structures that can take months to manufacture. Recent developments with high-temperature polymeric tooling, such as the ULTEM 9085 material, show great promise for low-cost, energy-saving tooling options for the polymer composites industry. In addition, these projects will explore the use of sparse-build tools, minimizing material use for the needs of the composite process. Composites are high-strength materials that are used in a wide range of industries and can be used for lightweighting, a key strategy for reducing energy use.
“Maturation of High-Temperature Selective Laser Sintering (SLS) Technologies and Infrastructure“
Northrop Grumman Aerospace Systems
Led by Northrop Grumman Aerospace Systems, in partnership with several industry team members, this project will develop a selective laser sintering process for a lower-cost, high-temperature thermoplastic for making air and space vehicle components and other commercial applications. In addition, recyclability and reuse of materials will also be explored to maximize cost savings and promote sustainability.
“Thermal Imaging for Process Monitoring and Control of Additive Manufacturing“
Penn State University Center for Innovative Materials Processing through Direct Digital Deposition (CIMP 3D)
Led by Penn State University, in partnership with several industry and university team members, this project will expand the use of thermal imaging for process monitoring and control of electron beam direct manufacturing (EBDM) and laser engineered net shaping (LENS) additive manufacturing processes. Improvements to the EBDM and LENS systems will enable 3D visualization of the measured global temperature field and real-time control of electron beam or laser power levels based on thermal image characteristics. These outcomes will enable the community to have greater confidence on part properties and quality using these technologies.
“Rapid Qualification Methods for Powder Bed Direct Metal Additive Manufacturing Processes“
Case Western Reserve University
Led by Case Western Reserve University, in partnership with leading aerospace industry companies and other industry and university team members, this project will improve the industry’s ability to understand and control microstructure and mechanical properties across EOS Laser Sintering and Arcam Electron Beam Melting powder bed processes. Process-based cost modeling with variable production volumes will also be delivered, providing the community with valuable cost estimates for new product lines. The outcomes from this project will deliver much needed information to qualify these production processes for use across many industries.
Corrosion nibbling away on a $30 million F-15 fighter jet is a bad thing, and the paint covering one is more than camouflage—it is a sophisticated multilayer coating system that also provides corrosion protection.
A typical coating system comprises an inorganic conversion coating, a primer and a topcoat. A conversion coating is not applied directly; rather, the surface of the metal is “converted” into a coating layer by means of a chemical or electrochemical reaction. Anodizing is an example of a conversion coating. Presumably, the native oxides on metallic surfaces could be classified as a type of conversion coating, too.
Chromate conversion coatings are among the most effective corrosion-inhibiting coatings for aluminum. Most aircraft are constructed of aluminum base alloys, and, obviously, avoiding corrosion is highly desirable. Unfortunately, hexavalent chromium is carcinogenic to humans, and, in 2009, DOD committed to eliminating chromate conversion coatings from its aircraft fleet.
What to replace them with is the question that a group at the Missouri University of Science and Technology is addressing. ACerS Fellow and Society director, Bill Fahrenholtz, is working with Missouri S&T metallurgist, Matt O’Keefe, on rare earth base corrosion-inhibiting coatings. The project was named one of only six “2012 Projects of the Year” by DOD’s Strategic Environmental Research and Development Program. SERDP’s mission is to “meet DOD’s environment challenges,” through programs it sponsors in partnership with EPA and DOE.
Fahrenholtz and O’Keefe have been studying coatings incorporating rare-earth compounds of cerium and praseodymium and the mechanisms by which they inhibit corrosion. Their experiments show that rare-earth compounds are not inherently protective compounds, but, in the right circumstances, they are good alternatives to chromate coatings. Cerium-based compounds work well as corrosion protective conversion coatings. Praseodymium-based inhibitors are dispersed in the primer coating, where they migrate to the surface to inhibit corrosion.
The group is studying the coatings on substrates made of two aluminum base alloys commonly used in aerospace applications, 2024-T3 and 7075-T6. Both are susceptible to localized galvanic corrosion.
The quality of the Ce-base conversion coating is strongly dependent on processing parameters, especially surface preparation. Aluminum is an electrochemically active material, which narrows the window where good coatings are achievable. In a phone interview, Fahrenholtz says, “We walk a fine line between getting a panel that is electrochemically active enough to make the coating, but not so active that it dissolves away.” Within that narrow window, he says, processing conditions that produce the best coatings also tend to favor formation of subsurface crevices.
According to Fahrenholtz, the Ce coating covers 90 percent or more of the surface and prevents corrosion by forming a simple barrier layer. However, up to 10 percent of the surface may be exposed to crevices. Using element mapping tools, such as focused ion beam/scanning electron microscopy, the team determined that oxides form within the crevices; during the salt spray exposure, corrosion products build up within the crevice, effectively closing it as it fills with oxide and providing a self-limit to the extent of corrosion. However, they also found that the corrosion protection of the cerium conversion coatings is strongly dependent on the phase, structure, pH and processing parameters. When processed properly, the conversion coating meets the military requirement to inhibit corrosion for two weeks in the ASTM B117 salt spray test.
Praseodymium-base inhibitors are not used as coatings themselves; rather, Pr2O3 or Pr6O11 powders are dissolved in the epoxy primer coating. The dissolved praseodymium ions inhibit corrosion of the substrate by migrating through the primer to the intermetallic, electrochemically active areas of the substrate, where it forms a compound over the intermetallic regions. Fahrenholtz says the compound that forms is a praseodymium hydroxycarbonate, however, the exact phase and composition are not know. “It is a really difficult compound to isolate,” he says.
The Pr-epoxy primer approach was recognized in 2007 as a R&D 100 winner. Deft, Inc. (Irvine, Calif.) is an industrial partner on the project and incorporates the Pr inhibitors in several of its primer products.
Sounding a little like a proud father, Fahrenholtz says “Because this is now a commercial product, it’s pretty much a finished project, and our work on it is done.”
The coatings are already in-service on F-15 aircraft and Apache helicopters, and there are plans to apply them to other military aircraft systems.
Work continues, however, on the Ce conversion coatings. Fahrenholtz says there are applications for this family of coatings in commercial aviation, military aviation and automotives. He says automobile weight reduction, for example, drives the development of materials like aluminum and magnesium, which are more reactive and need to be protected from the environment.
These CT scans showing the formation of microcracks in ceramic composites under applied tensile loads at 1,750 degrees Celsius were obtained at Berkeley Lab’s Advanced Light Source using a unique mechanical testing rig. Credit: Ritchie; LBNL.
“Failure is not an option” applies to ultrahigh temperature ceramics and ceramic composites for extreme environments. UHTC materials are expected to see service temperatures upwards of 1,500°C for applications that include hypersonic aircraft, scramjet engines, rocket propulsion systems, atmospheric reentry and next-generation gas turbine engines.
While failure may not be an “option,” it is always a possibility, and engineers developing these materials are challenged with testing them at temperatures high enough to generate meaningful data, especially with regard to mechanical properties. Data are critical to validating and tweaking the models used predict the materials’ performance and, ultimately, their safety.
Designing experiments that can test UHTC materials under load and at very high temperatures is itself an engineering challenge. Issues include designing furnaces that can reach test temperatures, fixture materials, accurate temperature measurement, controlling atmospheres and more.
A group at Berkeley Lab published a new paper in Nature Materials (pdf) on their work use of in-situ X-ray computed microtomography (CT scanning) of UHTC silicon carbide fiber-silicon carbide matrix composites that are subject to tensile loads at temperatures up to 1,750°C. The technique produces 3D images of microcracks in solid objects with a resolution of about one micron. The technique itself is nondestructive, so the observed damage comes only from the effects of load and temperature.
The group turned to in-situ CT scanning as a way to study better understand the risk of failure in extreme service conditions. In a press release, corresponding author of the study and ACerS Fellow Rob Ritchie says, “Complexity in composition brings complexity in safe use. For ceramic composites in ultrahigh temperature applications, especially where corrosive species in the environment must be kept out of the material, relatively small cracks, on the order of a single micron, can be unacceptable.”
Key to evaluating risk of failure is understanding the mechanisms of crack formation and growth. As the authors say the paper, “Measurements made a high temperature are the only faithful source of the details of failure.” The paper further explains, “Exactly how microcracks are restrained by such a tailored microstructure becomes the central question for the materials scientist, who seeks to find the optimal composition or architecture, and the design engineer, who must predict the failure envelope.”
The group tested two composite configurations: a single-tow SiC fiber-fiber matrix composite and a textile-type carbon fiber-SiC matrix composite. Samples were tested at 1,750°C at tensile load starting at 10 newtons and ranging until failure (which was, in one case, 127 newtons) The paper reports that the 3D images “reveal a wealth of information” on the interior failure mechanisms of the two composite configurations they tested, including the locations of the failure of individual fibers, the load a failure, the extent to which fibers relaxed after breaking, the opening displacement of matrix cracks and the 3D surface morphology of surface matrix cracks.
While nobody disputes that 1,750°C is a very high temperature, there are some materials that are expected to be used at even higher temperatures. For example, refractory metal borides like ZrB2 and HfB2 are candidates for the leading edges of hypersonic vehicles and service temperatures of more than 2,000°C are expected. Collecting realistic mechanical test property data at these temperatures is not an off-the-shelf capability.
In the January/February issue of the Bulletin includes a case study by a group at the Missouri University of Science and Technology under the guidance of professors Bill Fahrenholtz and Greg Hilmas on how they designed and built a system for testing mechanical properties of UHTCs at temperatures up to 2,600°C. To get the desired furnace temperatures, they turned to induction heating. This choice led to some electrical isolation and atmosphere control challenges. The system has been successfully validated for bend testing of ZrB2 and ZrB2–30SiC composites. Be sure to read it when the Bulletin arrives in your mailbox in late December.
Don’t get the Bulletin? You can by becoming a member! The Jan/Feb 2013 Bulletin will also be available online until late February 2013.
The Berkeley team’s paper is “Real-time quantitative imaging of failure events in materials under load at temperatures above 1,600°C” by H.A. Bale, A. Haboub, A.A. MacDowell, J.R. Nasiatka, D.Y. Parkinson, B.N. Cox, D.B. Marshall and R.O. Ritchie, Nature Materials (doi:10.1038/NMAT3497).
There were several pre-MS&T’12 events over the weekend before the mega-meeting’s official reception Sunday night, including the start of The American Ceramic Society’s Annual Meeting, a roundtable meeting of the Society’s division leaders, division executive committee meetings, several student-based activities and the Frontiers of Science and Society—Rustum Roy Reception and Lecture.
Here are what some of the events looked like:
Check ‘em out:
(Nature) One of the greatest drivers of materials research today is its potential economic impact. And yet it is a sad fact that many materials science concepts developed in research laboratories will never become a commercial reality. Why is that? And what could be done to improve the commercial prospects of new materials? Answers to these questions may be found by venturing into the world of arts and consulting with social scientists. There are an increasing number of opportunities to explore these interfaces. One such opportunity was the inaugural Inspiring Matter conference held at the Royal College of Art in London in April. Artists, product designers, architects, scientists and social scientists provided insights into their involvement with the development and application of new materials. For example, Mike Davies, an architect known for his work on the Millennium Dome and the Pompidou Centre, proposed his vision of the future of buildings with biomimetic skins that respond to the environment, can harvest energy, and can understand and respond to the needs and moods of their inhabitants. And Bradley Quinn, a trend forecaster, presented new clothing concepts inspired by self-assembly, light- and heat-responsive materials and aerosol technology (spray-on clothing—see image above). Although some of these ideas might seem far-fetched, they reveal how, unconstrained by scientific trends or perceived limitations, potential new applications and commercial opportunities could be opened up by artistic and scientifically creative minds working together. Not only that, but art itself could benefit from artists increasing their knowledge of new materials and processes, as Nature Materials has explored previously.
(Physics) Running a finger over an irregular object is a good way to gauge its shape. In 1986, three scientists built a device to do essentially the same thing at the atomic level and published their results in Physical Review Letters. Using a tiny diamond stylus, their atomic force microscope traced out a surface with better than nanometer resolution. The device caught on quickly and with further improvements became a widely used laboratory tool for mapping surfaces with molecular precision, even for biological samples. In 1981, Gerd Binnig and Heinrich Rohrer of the IBM Research Laboratory in Zurich invented the scanning tunneling microscope. In this instrument, a sharp metal point, or “tip,” is held just above the surface of an object, close enough that a voltage induces a small current to flow across the gap between tip and surface through the phenomenon of quantum mechanical tunneling. If the tip, as it traverses an object, is moved up and down so as to keep the tunneling current fixed, its movements record the topography of the object’s surface. The earliest results had subnanometer resolution, enough to show surface features with single-atom dimensions; modern STMs can do much better. However, the STM can only scan objects that conduct electricity.
As demand increases for lithium, the essential element in batteries for everything from cameras to automobiles, a researcher at Missouri University of Science and Technology is studying potential disruptions to the long-term supply chain the world’s lightest metal. Although the current dominant battery type for hybrid electric vehicles is nickel metal hydride, lithium-ion battery technology is considered by many to be the “power source of choice for sustainable transport,” says Ona Egbue, a doctoral student in engineering management. “Lithium batteries are top choices for high-performance rechargeable battery packs,” Egbue says. “Batteries make up 23 percent of lithium use and are the fastest growing end use of lithium.” The US is a major importer of lithium. The majority of known lithium reserves are located in China, Chile, Argentina and Australia. Together these regions were also responsible for more than 90 percent of all lithium production in 2010, not including U.S. production. “More than 90 percent of lithium reserves - what is economically feasible to extract - are in just four countries,” Egbue says. “The geopolitical dynamics of this distribution of lithium supplies has largely been ignored.”
Thanks to developments in 3D printing technology, Beauty the Bald Eagle has a new beak and a new lease on life. The bird, who was shot in the face by a poacher in 2005, was rescued by Jane Fink Cantwell of Birds of Prey Northwest. Thanks to Nate Calvin of Kinetic Engineering Group, Beauty can use her new polymer prosthetic to feed herself, preen, and drink. Working with Nate Calvin from the Boise tech company, Kinetic Engineering Group, Birds of Prey Northwest has helped to restore a classic American symbol to her former glory. Using the 3D CAD software, SolidWorks, KEG was able to model the new beak with the input of a number of wildlife experts.