Design and Phase-Field Simulation of Core-Shell Microstructure in TiNb Binary Alloy

Abstract:

The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations, where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition, and then the formation mechanism of core-shell structure was revealed. In addition, the influences of initial temperature gradient, average temperature, and initial concentration distribution of the system on the core-shell structure were investigated. Results show that the initial concentration gradient is the key factor for forming the core-shell structure. Besides, larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure, which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy. As a theoretical basis, this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.