Throughout the centuries, metals and their alloys have played a crucial role in the development of global societies. From ancient times to the present day, humans have relied on advancements in metals technologies for various aspects of life, including defense, housing, transportation, energy, and health. However, it is important to note that the possibilities in metals production have largely been limited to melt-based processes, such as casting, followed by a range of thermomechanical steps to achieve the desired microstructures and, consequently, performance.
A grand challenge in the production of next-generation transformative materials at scale is to develop manufacturing methods that can avoid the constraints on chemistry and structure imposed by melt-based processing approaches and exploit the potential of non-equilibrium synthesis pathways to produce materials and components with extraordinary performance.
Solid Phase Processing (SPP) is one high-potential approach to meeting this grand challenge for metals synthesis and fabrication. In SPP methods, a high shear strain is introduced into the material, creating a mechanical-thermal coupling that facilitates diffusional processes and phase transformations without requiring the alloy to be melted. Because the thermal energy required for material flow is generated by the frictional effects of the process itself, the need for external heating is eliminated or sharply reduced. As a result, the potential exists for rapid heating and cooling combined with kinetically driven atomic movement to enable the controlled production of metastable phases.
Through the Solid Phase Processing Science Initiative (SPPSi), PNNL has conducted extensive research on the intricate physics involved in SPP methods. This research has provided valuable insights into the kinetic and thermodynamic pathways that are activated when materials are subjected to high shear strain during synthesis and fabrication. These insights have not only accelerated the development of innovative SPP approaches but also paved the way for the demonstration of scalable pathways for the efficient and cost-effective production of high-performance technology-enabling materials.