[Image above] Telephone technology owes much of its evolution to improved materials. The next wave of innovation will demand focused research. Credit: Nick Sieger; Flickr CC 2.0
Many of us have experience using generations of telephone technologies: party line phones, touch-tone phones, cordless phones, cell phones, and now smartphones.
We’ve come a long way. Only one century ago, nobody could have predicted smartphones, let along the extent to which we build and manage our lives around these devices.
And there will come a day when our descendants look upon our slick smartphones and think, “how quaint.”
It takes time and resources to develop the science that will lead to new materials and materials engineering—and consensus on priorities.
In September 2016, the National Science Foundation sponsored a workshop on the role of ceramic and glass science research in meeting society’s grand challenges. Organized by Katherine Faber, Jennifer Lewis, Clive Randall, and Gregory Rohrer, 42 leading researchers from the United States and abroad met to tease out the research priorities that will lead to new materials for far-horizon applications.
Faber, who was lead organizer, says, “Our workshop participants identified some especially challenging research directions, which, if realized, would enable advancements across the energy, manufacturing, security, and healthcare sectors.”
The workshop has impact beyond NSF, according to Faber. “The National Academies of Sciences, Engineering, and Medicine is currently conducting a decadal survey on frontiers in materials research. Our report is especially timely to inform the survey of the far-reaching opportunities in glass and ceramics research,” she says.
The workshop was organized around five themes: ceramic processing science, defect-enabled phenomena, low-dimensional phenomena, ceramics for extreme environments, and glasses and high-entropy materials. Four materials classes were considered: amorphous materials, oxides, nonoxides, and composites.
Eight grand challenges emerged and are reported in an open access article published in the May 2017 Journal of the American Ceramic Society. Two ideas were common to all themes and materials: the importance of computation materials science, and the need for characterization tools capable of characterizing materials at atomic-scale lengths and for measuring properties as high temperature and pressure.
The ambition of the challenges speaks for itself, as the following synopsis shows.
Theme: Ceramic processing science
Challenge #1—Ceramic processing: Programmable design and assembly
This challenge recognizes that better understanding of processing methods could lead to new functionality in materials and better engineering of materials to achieve desired properties. Issues include developing multiscale modeling techniques, understanding external field effects in colloidal systems, additive manufacturing, and cold sintering.
“The major progress in colloidal science, guided self-assembly, coating methods, and 3-D printing, coupled with cold sintering, offers new opportunities to design and integrate dissimilar materials that were previously unimaginable. By establishing a new ceramics processing paradigm, new materials will be created with unique combinations of matter, architecture, and properties that require fewer trade-offs.”
Theme: Defect-enabled phenomena
Challenge #2—The defect genome: Understanding, characterizing, and predicting defects across time and length scales
New thinking looks at defects as tunable parameters to gain new kinds of properties in materials. Areas that show promise already include thin films, ferroelectrics, and solid electrolytes. Manipulating defects may play into low-temperature synthesis mechanisms.
“…an implicit control of defect structure is supporting or even driving the desired effects. Embracing these considerations for assembled structures, including defect engineering as an additional design parameter, processing tunable defect structures will open access to a new range of materials and phenomena.”
Challenge #3—Functionalizing defects for unprecedented properties
Taking Challenge #3 further, what new properties would be possible if defects themselves could be engineered for specific functions? Could new materials with new properties be designed by engineering defect properties?
“To achieve the goals…, the development of a defect genome and the functionalization of defects as toolkits for materials design will require comprehensive understanding of relevant defect interactions, defect dynamics, and defect–property relations.”
Theme: Low-dimensional phenomena
Challenge #4—Ceramic flatlands—Defining structure–property relations in free-standing, supported, and confined two-dimensional ceramics
Two-dimensional materials take the form of free-standing sheets, supported coatings, or the grain boundary interfaces known as complexions. Discovery of new 2-D materials outpaces understanding of their properties and, therefore, the ability to design with them.
“The next obvious step in advancing the science of 2-D ceramics is understanding structure–property relations. To date, it is not possible to predict how the properties of oxides only known to exist in the bulk state change when those oxides are made into nanometer thin sheets.”
Theme: Ceramics for extreme environments
Challenge #5—Ceramics in the extreme: Discovery and design strategies
Environments for which a material does not exist is by definition an extreme environment. Examples include hypersonic flight; aerospace propulsion; advanced nuclear energy; and tribological, superabrasive, and armor materials. Severe environments are difficult to replicate, which makes property data very difficult to achieve. Modeling and simulation are essential tools.
“Most extreme environments will likely require multimaterial systems, wherein performance [depends] on the interplay among [individual constituents]. …two challenges are identified in ceramics for extreme environments, one related to discovery and design strategies for new materials and the other to improved understanding of complex systems…under extreme thermal, chemical, and mechanical environments.”
Challenge #6—Ceramics in the extreme: Behavior of multimaterial systems
Extreme environments push the limits on all materials exposed. Unexpected interactions between materials in extreme environments could have catastrophic consequences.
“The complexity of extreme environments favors reliance on multiphase/multielement materials having tailored microstructures and architectures. A scientific approach that captures the complexity of salient thermochemical and thermomechanical material interactions is essential.”
Challenge #7—Understanding and exploiting glasses and melts under extreme conditions
Glasses form when the kinetic demands of thermodynamic equilibrium cannot be met, usually by manipulating cooling rate. Better understanding of factors such as pressure or other gradients—possibly through collaboration with the geoscience community—could lead to new glasses and better performance of known glasses.
“By studying the responses of glasses and melts to extremes in temperature, pressure, deep super-cooling or steep chemical, electrochemical, and magnetic gradients using in situ or operand characterization tools and methods, knowledge of the glassy state can be substantially extended.”
Challenge #8—Rational design of functional glasses guided by predictive modeling
Designing new glasses for specific properties and functionalities requires shedding empirically based glass research and adopting a physics based understanding of composition and processing conditions. This will require development of multiscale models for oxide, nonoxide, and multicomponent systems.
“…to design multifunctional glasses, models at different scales are needed to predict manufacturing-related attributes, for example, temperature-dependent viscosity, liquidus temperatures, and refractory compatibility, as well as the relevant end-use properties, for example, elastic moduli, hardness, and damage resistance for cover glass in personal electronics.”
The open-access paper, published in the May 2017 Journal of the American Ceramic Society, is “The role of ceramic and glass science research in meeting societal challenges: Report from an NSF-sponsored workshop” (DOI 10.111/jace.14881).