Defect-characterized phase transition kinetics

Abstract

Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field.

Rapid Phase Transitions of Thermotropic Glycolipid Quasicrystal and Frank‐Kasper Mesophases: A Mechanistic Rosetta Stone

“…proceeds through introduction of two planar defects into only the (100) plane of the A15 lattice to directly provide the Z lattice. [24,25] It is also of interest that SAXS investigations have been reported for other diffusionless martensitic phase transitions between block copolymer micelle mesophases, including ones involving the introduction of stack faults. [26] The remaining questions for the proposed thermotropic martensitic A15!σ phase transition of Figure 8 then become, what is the driving force behind this transformation, and can an answer provide new insights for reliably predicting the relative stabilities of other canonical and noncanonical thermotropic soft matter mesophases and the mechanistic nature of order-order phase transitions connecting them?…”

Predicting and accessing metastable phases

“…Our observations align with Wigner's stipulation that, with increasing fluence, the defect concentration in a phase increases, and hence, the internal energy of that phase is also increased. 63 At the same time, the increased defect concentration will act to lower the nucleation barrier for the kinetics to drive a phase transition 64 which, with the increased internal energy, will cause the phase transition to a metastable phase. At this time we cannot identify which defects are responsible for the phase transformations.…”

Rapid Phase Transitions of Thermotropic Glycolipid Quasicrystal and Frank‐Kasper Mesophases: A Mechanistic Rosetta Stone

“…Chemie alloys that proceeds through introduction of two planar defects into only the (100) plane of the A15 lattice to directly provide the Z lattice. [24,25] It is also of interest that SAXS investigations have been reported for other diffusionless martensitic phase transitions between block copolymer micelle mesophases, including ones involving the introduction of stack faults. [26] The remaining questions for the proposed thermotropic martensitic A15!σ phase transition of Figure 8 then become, what is the driving force behind this transformation, and can an answer provide new insights for reliably predicting the relative stabilities of other canonical and noncanonical thermotropic soft matter mesophases and the mechanistic nature of order-order phase transitions connecting them?…”