Splitting behavior of lamella

Abstract

Lamella is a unique microstructure in matters that possesses special properties. The formation and evolution of lamellar microstructures are crucial for achieving super abilities, while the mechanisms of lamellar formation and evolution at the nanoscale are unclear. Driving by the interesting while uncovered micromechanism in lamellar microstructure evolution, we performed the phase-field simulation and experiment to investigate the multiple splitting behaviors of lamellar Ti-Al alloys. The splitting mode of lamella is discovered, inner splitting (IS) and outside splitting (OS). The originations of splitting are found to come from the high interfacial energy of step-like interface between γ variants for the IS, and the stress concentration at α₂/γ interface drives step-like interface for the OS. The lamellar splitting is complied with the energy change in matter, decreasing in total free energy and elastic energy, while increasing in interfacial energy. These findings provide the new mechanisms of internal lamellar interface breaking driven by the interfacial energy. Therefrom, the expected matter features will be achieved by the strategy of microstructure modulation and optimization.