TiNb二元合金中核壳结构的设计及相场模拟

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

摘要:

采用相场模拟对块体TiNb二元合金中的核-壳结构进行了设计和研究，通过精确控制TiNb合金体系中调幅分解过程的初始和边界条件，以获得不同的核-壳结构，并揭示了核-壳结构的形成机理。此外，研究了体系初始温度梯度、平均温度和初始浓度分布对核-壳结构的影响。结果表明，初始浓度梯度是形成核-壳结构的关键因素。此外，较大的初始温度梯度和较高的平均温度能促使核-壳结构的形成，并可通过调节TiNb合金中富铌区的初始浓度分布来稳定核-壳结构。作为理论基础，本研究为制备具有特殊核-壳结构和理想力学与物理性能的TiNb基合金以及其它材料提供了一种新颖且简单的策略。

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.