The evolution of materials; their synthesis, shaping, and performance; and the engineering of artifacts and systems to meet societal demands are inextricably interwoven. In this article, we describe an evolving scenario of the relationship between materials and engineering that provides a framework for the articles that explore various facets of this theme in this special issue of MRS Bulletin.

The materials characterization universe is as large and multifaceted as the materials and engineering fields combined. Many methods have evolved over decades, or even centuries, from quite rudimentary tools to extremely sophisticated instruments. Measurement and testing of materials span properties from mechanical, to electrical, to thermal; materials classes from metals, to semiconductors, to insulators, with ceramics, polymers, and composites somewhere in between; scales from atomic through nano-, micro-, meso-, and macroscopic; and times spanning picoseconds to years in practice, to eons in simulation. The technical context of a materials measurement ranges from fundamental science, often with no immediately transparent connection, to future engineering applications, to quite practical “real-world” field tests that can predict performance and—one hopes—prevent component failure. Materials measurement methods have grown out of distinct disciplinary homes: physics, chemistry, metallurgy, and, more recently, biology and environmental science. Drawing from the broad expanse of materials characterization techniques, we offer a perspective on that breadth and cite examples that are illustrative of the crucial role such techniques have played and are playing in the technologies of today.

Major advances have been made over the past 30 years in the development of an integrated computational materials design (ICMD) technology. The hierarchical structure of its methods, tools, and supporting fundamental materials databases is reviewed here, with an emphasis on successful applications of CALPHAD (calculation of phase diagrams)-based tools as an example of ICMD, expressing mechanistic understanding in quantitative form to support science-based materials engineering. Opportunities are identified for rapid expansion of CALPHAD databases, as well as a major restructuring of materials education.

The global automotive industry is facing challenges in several key areas, including energy, emissions, safety, and affordability. Lightweighting is one of the key strategies used to address these challenges. Maximizing the weight reduction (i.e., minimizing vehicle weight) requires a systems-engineering design optimization and iteration process that combines material properties and manufacturing processes to meet product requirements at the lowest mass and/or cost. Advanced high-strength steels, aluminum and magnesium alloys, and carbon-fiber-reinforced polymers have emerged as important materials for automotive lightweighting. This article presents examples of how coupling materials science with innovative manufacturing processes can provide lightweight solutions in automotive engineering.

Selection of materials systems for aerospace applications, such as airframes or propulsion systems, involves multiple and challenging requirements that go beyond essential performance attributes (strength, durability, damage tolerance, and low weight). Materials must exhibit a set of demanding properties, be producible in multiple product forms, and demonstrate consistent high quality. Furthermore, they must be both commercially available and affordable. The list of materials meeting these requirements is not long. Integration and transformation of such highly engineered materials into airframe structures is likewise complex. The Boeing 747, for instance, requires more than 6,000,000 components from numerous materials systems and suppliers worldwide. This necessitates that materials be stable and that material design and structure engineering close on effective solutions simultaneously. High-temperature turbine engines demand strong, lightweight, high-temperature materials balanced by high durability and reliability in a severe service environment. Such applications provide remarkable examples of how engineering imperatives influence materials research and development for metallic and composite materials in terms of material chemistry, fabrication, and microstructure.

Materials play a critical enabling role in many energy technologies, but their development and commercialization often follow an unpredictable and circuitous path. In this article, we illustrate this concept with the history of lithium-ion (Li-ion) batteries, which have enabled unprecedented personalization of our lifestyles through portable information and communication technology. These remarkable batteries enable the widespread use of laptop and tablet computers, access to entertainment on portable devices such as hand-held music players and video game consoles, and enhanced communication and networking on personal devices such as cellular telephones and watches. A similar transformation of transportation to electric cars and of the electricity grid to widespread deployment of variable renewable solar and wind generation, effortless time-shifting of energy generation and demand, and a transition from central to distributed energy services requires next-generation energy storage that delivers much higher performance at lower cost. The path to these next-generation batteries is likely to be as circuitous and unpredictable as the path to today’s Li-ion batteries. We analyze the performance and cost improvements needed to transform transportation and the electricity grid, and we evaluate the outlook for meeting these needs with next-generation beyond Li-ion batteries.

This article discusses the role of materials science in the growth and processing of silicon that made modern microelectronics possible. The influence of defects on the electronic properties of silicon is explored, followed by the production of electronic-grade silicon and its conversion into macroscopically dislocation-free doped silicon crystals. The intricacies of dopant distributions in as-grown crystals are also discussed. Oxidation, ion implantation, and metallization are essential elements of device processing, and their salient features are emphasized. The electromigration behavior of interconnects and attempts to prevent it are also introduced.

Protein- and peptide-based structural biopolymers are abundant building blocks of biological systems. Either in their natural forms, such as collagen, silk, and fibronectin, or as related synthetic materials, they can be used in various technologies. An emerging area is that of biomimetic materials inspired by protein-based biopolymers, which are made up of small molecules rather than macromolecules and can therefore be described as supramolecular polymers. These materials are very useful in biomedical applications because of their ability to imitate the extracellular matrix in both architecture and the capacity to signal cells. This article describes important features of the natural extracellular matrix and highlights how these features are being incorporated into biomaterials composed of biopolymers and supramolecular polymers. We particularly focus on the structures, properties, and functions of collagen, fibronectin, and silk, and the supramolecular polymers inspired by them as biomaterials for regenerative medicine.

Concrete is the most used material on Earth except for water. Thus, there is much to be gained through improvements in the manufacturing of cement and the production of concrete to meet societal demand in a sustainable manner. This article reviews recent developments in three areas that have the potential to transform the ways in which infrastructure is specified, designed, and constructed: (1) expanding the use of supplementary cementitious materials and the identification of alternative supplementary cementitious materials, (2) growing the use of alternative cements and binder technologies, and (3) developing alternative reinforcement options. Strategies to facilitate the transfer of these emerging and next-generation materials and technologies from the research arena into real structures are also discussed.

Carbon, with its variety of allotropes and forms, is the most versatile material, and virtually any combination of mechanical, optical, electrical, and chemical properties can be achieved with carbon by controlling its structure and surface chemistry. The goal of this article is to help readers appreciate the variety of carbon nanomaterials and to describe some engineering applications of the most important of these. Many different materials are needed to meet a variety of performance requirements, but they can all be built of carbon. Considering the example of supercapacitor electrodes, zero- and one-dimensional nanoparticles, such as carbon onions and nanotubes, respectively, deliver very high power because of fast ion sorption/desorption on their outer surfaces. Two-dimensional (2D) graphene offers higher charge/discharge rates than porous carbons and a high volumetric energy density. Three-dimensional porous activated, carbide-derived, and templated carbon networks, with high surface areas and porosities in the angstrom or nanometer range, can provide high energy densities if the pore size is matched with the electrolyte ion size. Finally, carbon-based nanostructures further expand the range of available nanomaterials: Recently discovered 2D transition-metal carbides (MXenes) have already grown into a family with close to 20 members in about four years and challenge graphene in some applications.

Mimicking the resilience offered by hard biomaterials, such as mollusk shells and beaks, has been among the most sought-after engineering pursuits. Technological advances in fabrication methods have provided pathways for using different materials to create architected structural metamaterials with hierarchy and length scales similar to those found in nature. Inspiration from nature has led to the creation of structural metamaterials, or nanolattices, with enhanced mechanical properties caused by hierarchical ordering at various length scales, ranging from angstroms and nanometers for the material microstructure to microns and millimeters for the macroscale architecture. The inherent periodicity and high surface-area-to-volume ratios of nanolattices make them useful for a variety of applications, including photonics, photovoltaics, phononics, and electrochemical systems. This article provides an overview of current three-dimensional architected metamaterials, including their fabrication methods, properties, applications, and limitations.

In this article, we review recent research progress on ultraflexible organic thin-film devices and their emerging applications. We describe progress on devices such as organic thin-film transistors, organic photovoltaic cells, and organic light-emitting diodes that are manufactured on ultrathin plastic films with micrometer-scale thicknesses. These ultraflexible organic devices have been utilized to realize new applications, including wearable and biomedical devices.

From the photoinduced transport of energy that accompanies photosynthesis to the transcontinental transmission of optical data that enable the Internet, our world relies and thrives on optical signals. To highlight the importance of optics to society, the United Nations designated 2015 as “The International Year of Light and Light-based Technologies.” Although conventional optical technologies are limited by diffraction, plasmons—collective oscillations of free electrons in a conductor—allow optical signals to be tailored with nanoscale precision. Following decades of fundamental research, several plasmonic technologies have now emerged on the market, and numerous industrial breakthroughs are imminent. This article highlights recent industrially relevant advances in plasmonics, including plasmonic materials and devices for energy; for medical sensing, imaging, and therapeutics; and for information technology. Some of the most exciting industrial applications include solar-driven water purifiers, cell phone Raman spectrometers, high-density holographic displays, photothermal cancer therapeutics, and nanophotonic integrated circuits. We describe the fundamental scientific concepts behind these and related technologies, as well as the successes and challenges associated with technology transfer.

The past decade has seen remarkable progress in the development of the nitrogen-vacancy (NV) defect center in diamond, which is one of the leading candidates for quantum information technologies. The success of the NV center as a solid-state qubit has stimulated an active search for similar defect spins in other technologically important and mature semiconductors, such as silicon carbide. If successfully combined with the advanced microfabrication techniques available to such materials, coherent quantum control of defect spins could potentially lead to semiconductor-based, wafer-scale quantum technologies that make use of exotic quantum mechanical phenomena like entanglement. In this article, we describe the robust spin property of the NV center and the current status of NV center research for quantum information technologies. We then outline first-principles computational modeling techniques based on density functional theory to efficiently search for potential spin defects in nondiamond hosts suitable for quantum information applications. The combination of computational modeling and experimentation has proven invaluable in this area, and we describe the successful interplay between theory and experiment achieved with the divacancy spin qubit in silicon carbide.

Additive manufacturing (also known as 3D printing) is considered a disruptive technology for producing components with topologically optimized complex geometries as well as functionalities that are not achievable by traditional methods. The realization of the full potential of 3D printing is stifled by a lack of computational design tools, generic material feedstocks, techniques for monitoring thermomechanical processes under in situ conditions, and especially methods for minimizing anisotropic static and dynamic properties brought about by microstructural heterogeneity. This article discusses the role of interdisciplinary research involving robotics and automation, process control, multiscale characterization of microstructure and properties, and high-performance computational tools to address each of these challenges. Emerging pathways to scale up additive manufacturing of structural materials to large sizes (>1 m) and higher productivities (5–20 kg/h) while maintaining mechanical performance and geometrical flexibility are also discussed.

During the past two decades, numerous biomaterials and soft materials, including ceramics, polymers, and their composites, have been fabricated for various biomedical devices and applications in tissue engineering using three-dimensional (3D) printing. This article offers a brief overview of some of the biomaterials and soft materials fabricated using some notable 3D printing techniques and related applications. A brief perspective regarding future directions of this field is also provided.

Engineering, whether in the form of product development or manufacturing processes, often drives the selection or creation of new materials in order to meet performance requirements. Conversely, development of new materials, or new ways to process materials, can lead to new engineering capabilities that, in turn, lead to new products or improved product performance. The interplay between materials and engineering is dynamic, ongoing, and critical to the success of many new products and industries. In this article, we take examples of this interplay from four technology companies in different industries developing widely different materials systems. Each example demonstrates the critical role that materials play in creating new products, new manufacturing methods, and even new design methodologies. Our examples come from polymer microfluidic devices, silicon- and nonsilicon-based microelectromechanical systems, and metals additive manufacturing.

Turning good ideas and discoveries in the laboratory into commercial and industrial products that succeed in the marketplace is a fraught affair. Most apparently promising leads never get that far, being derailed by lack of funding, unexpected technical hitches, excessive cost, consumer indifference, and other hurdles. This difficult transition without doubt weeds out some ideas that simply don’t have what it takes, but some casualties might have become success stories if the developmental process had been better handled. So what can you do to give your exciting discovery the best possible chance of being the start of something big? And how can universities, companies, and institutions prevent useful innovation from falling by the wayside?