Stress-induced Martensitic Grain Boundary Complexion Transitions

In recent years, grain boundary (GB) researchers have discovered that grain boundaries—or interfaces between differently oriented crystals—can exist in multiple distinct states, known as complexions. These complexion transitions can dramatically alter material properties such as strength, conductivity, and corrosion resistance. While thermally driven complexion transitions have been studied, the role of mechanical stress in triggering these transitions remains poorly understood. This project uses molecular dynamics simulations to investigate stress-induced martensitic complexion transitions at grain boundaries in body-centered cubic (BCC) metals. By applying controlled stress states to bicrystal models, the critical conditions for triggering structural transformations at grain boundaries are identified. Understanding these transitions has implications for predicting material behavior under mechanical loading and for designing alloys with tailored grain boundary properties.