Valery I. Levitas, a distinguished researcher in materials science, has published a groundbreaking review that delves into the intricate interplay between severe plastic deformations (SPD), phase transformations and chemical reactions (PTs/CRs), and microstructure evolution under high pressure. This comprehensive study, which integrates advanced mechanics and thermodynamics, offers new insights into the multifaceted interactions that occur at various scales—from atomistic to macroscale—providing a holistic understanding of materials behavior under extreme conditions.
The review highlights the transformative impact of SPD on high-pressure processes. SPD significantly reduces the pressure required for PTs/CRs, often by one to two orders of magnitude, and minimizes phase transformation hysteresis. This reduction not only facilitates the discovery of hidden metastable phases that would otherwise remain elusive but also replaces reversible PTs/CRs with irreversible ones. These findings are crucial for a range of applications, including the synthesis of new nanostructured phases, mechanochemical synthesis, and military applications.
Levitas’s research introduces a novel concept of plastic strain-induced PTs/CRs under high pressure, supported by a four-scale theory and simulations. This multi-scale approach encompasses atomistic, nano-, and scale-free phase-field methods, as well as macroscale simulations. These theoretical advancements are coupled with in situ experiments conducted in traditional and rotational diamond anvil cells, providing a robust framework for understanding and predicting material behavior under extreme conditions.
The integration of analytical, computational, and experimental approaches has revealed several new phenomena and resolved numerous long-standing puzzles in the field. This interdisciplinary methodology has also led to the identification of general rules governing these processes, paving the way for economic defect-induced synthesis of high-pressure phases and nanostructures. The study emphasizes the importance of complete characterization of heterogeneous scalar and tensorial fields to fully grasp the occurring processes.
The practical applications of these findings are vast and varied. They include high-pressure torsion, surface treatment, high-pressure tribology, and PTs/CRs in shear bands, which can lead to severe transformation/reaction-induced plasticity and self-blown-up processes. Beyond industrial applications, the research also sheds light on natural phenomena such as the mechanisms of deep-focus earthquakes and the appearance of microdiamonds in low-pressure-temperature Earth crust. Additionally, the study explores the intriguing possibility of the mechanochemical origin of life beyond Earth.
Levitas’s review not only highlights the achievements in the field but also outlines unresolved problems and future research directions. By addressing these challenges, researchers can further advance the understanding of materials behavior under high pressure and severe plastic deformations, ultimately driving innovation in various scientific and industrial domains.
This research represents a significant step forward in the field of materials science, offering a comprehensive framework for exploring the complex interactions between SPD, PTs/CRs, and microstructure evolution. The insights gained from this study have the potential to revolutionize both industrial processes and our understanding of natural phenomena, underscoring the importance of continued research and innovation in this critical area. Read the original research paper here.