纳米陶瓷颗粒/铝基复合材料常规凝固中，因受颗粒尺寸及熔体热/溶质扩散等效应制约，颗粒易偏聚于α-Al晶界，致使材料塑韧性显著降低。基于此，本项目提出超声辅助合金凝固诱导颗粒晶内分布进而提高合金强韧性的学术思想。以纳米TiB2/Al(Si)复合材料为研究对象，在其凝固中引入超声并辅以数值模拟，研究超声诱导TiB2晶内分布的动力学机制及其对熔体成分、工艺因素等的响应特性，并探究其强韧化机理。主要研究内容为：1）研究超声诱致熔体过冷及其温度/溶质场变化特征并揭示其诱发α-Al在TiB2上形核动力学机制；2）阐明α-Al长大阶段超声诱使TiB2被固液界面捕获作用机制并提出相应动力学判据；3）研究TiB2纳米尺度效应及晶内/界分布特征对合金强韧化的影响机制并构建“超声-颗粒分布-合金强韧化”关联模型。本项目实施有助于明晰超声下纳米颗粒在合金凝固中的行为特征，为铝合金强韧化提供新的设计方法和理论指导。

Due to the size effect of nano-ceramic particles as well as the heat effect and solute diffusion effect of the melt, the particles easily aggregate at the α-Al grain boundaries during the normal solidification of nano-creamic particle/Al matrix composites, leading to the significant decrease in ductility for the Al alloys. Based on which, this project proposes an academic thought that improves both the strength and ductility of the Al alloys by the intragranular distribution of particles induced by ultrasound-assisted solidification. This project focuses on the nano-TiB2/Al (Si) system, and plans to introduce ultrasound in the melts during the solidification. By combining simulation, the dynamic mechanism of ultrasound-induced intragranular distribution of TiB2 particles and its response characteristics to the melt composition and process factors, as well as the mechanisms of strength and ductility of composites, will be explored. The main research content includes:1) studying the effects of ultrasound-induced melt undercooling and the changes of the temperature/solute fields on the nucleation of α-Al and further reveal the dynamic mechanism of ultrasound-induced α-Al nucleation; 2) illuminating the mechanism of ultrasound-induced TiB2 particles engulfment by the solid/liquid interface in the stage of α-Al growth, and proposing a related kinetic criterion; 3) studying the nano-size effect of TiB2 particles and the influence distribution rules of TiB2 particles within the grains/along grain boundaries on the strength and ductility of composites, and building the correlation model of “ultrasound-particle distribution-strength and ductility of alloys”. The implementation of this project is helpful for understanding the behavior characteristics of nano-particles in the melt during the solidification under ultrasound and is expected to provide a novel design method and theoretical guidance for improving the strength and ductility of Al alloys.