The Role of Interfaces in Structural Materials – And a Glimpse Into the Future

Speaker: Dr. Christopher Marvel

Affiliation: Materials Science and Engineering, Lehigh University

Abstract: The study of interfaces in structural materials is a grand challenge and extensive research has been conducted in order to understand and ultimately control interfacial behavior. While more classical perspectives consider interfaces, such as grain boundaries, as 2D defects that are defined by the misorientation between two grains, a more modern perspective considers interfaces as “phase-like” structures that undergo first-order transitions similar to bulk phases. This new paradigm is generally referred to as the field of grain boundary complexions and increasingly more examples continue to show how grain boundary complexions can be leveraged to improve bulk material properties. In this talk, I will briefly describe several recent advances in grain boundary complexion research and then outline specific case studies of my research when interfaces were engineered to control microstructure evolution or improve thermomechanical properties in extreme environments. More specifically, I will discuss my research efforts to maximize nanocrystalline thermal stability, toughen armor ceramics against ballistic impacts, and develop mechanically alloyed high entropy materials. Within the description of each case study, I will also present examples of how advanced material characterization techniques, such as aberration-corrected scanning transmission electron microscopy and z-factor microanalysis, were applied to investigate materials on the atomic scale. Finally, I will conclude with an introduction to the recent effort at Lehigh University, entitled the Presidential Nano/Human Interfaces Initiative, which strives to revolutionize the way in which nanoscale interfaces can be experimentally and computationally investigated by revamping machine-human relationships and integrating data analytics into a scientific work environment.