Athermal resistance to interface motion in the phase-field theory of microstructure evolution

Area of Science:

• Materials Science
• Condensed Matter Physics
• Chemical Engineering

Background:

• The Ginzburg-Landau (GL) approach is a key theoretical framework for modeling phase transformations (PTs).
• Standard GL models often fail to capture experimentally observed microstructures and stress hysteresis in first-order PTs.
• These limitations hinder accurate predictions of material behavior under various conditions.

Purpose of the Study:

• To develop a modified Ginzburg-Landau (GL) method that incorporates athermal resistance to interface propagation.
• To address the limitations of existing GL models in simulating first-order phase transformations (PTs).
• To accurately reproduce experimentally observed microstructures and rate-independent stress hysteresis.

Main Methods:

• Introduction of oscillating stress fields, arising from defects or Peierls barriers, into the GL free energy functional.
• Incorporation of a jump in chemical energy to represent athermal resistance.
• Application of the modified GL approach to simulate first-order phase transformations.

Main Results:

• The developed method successfully arrests microstructural evolution, preventing convergence to a single phase.
• The model accurately reproduces experimentally observed microstructures that are typically lost in standard GL simulations.
• The approach yields rate-independent stress hysteresis, a critical feature of many first-order PTs.

Conclusions:

• The novel GL method provides a more accurate theoretical framework for first-order phase transformations (PTs).
• This approach overcomes essential drawbacks in conventional GL modeling, enhancing predictive capabilities.
• The method's applicability extends to various phenomena, including twinning, dislocations, and electric/magnetic phase transitions.