高熵合金中纳米孪晶瞬间形成机理研究

High entropy alloy is an advanced structural material. Generate of nanotwins can improve both strength and ductile of this material. Several discipline methods including the materials science and the dynamics and the computer science are combined together to start this research. In this work, the microstructure features of the nanotwins in the shear band in the high entropy alloy was investigated by the Three Dimensional Atom probe Analysis (3DAP) and HADDF-Spherical Aberration Corrected Scanning Transmission Electron Microscope (HADDF-STEM), and the effects of the interstitial elements and the grain sizes on the formation of the nanotwins were discussed, and the dislocation mechanism for the twinning of the high entropy alloy at high strain rate deformation was proposed. Formation of nanotwins in the high entropy alloys were simulated by the molecular dynamic method, and then the dynamic feasible physic model of formation of nanotwins in the high entropy alloy in a short time was also proposed. Finally, the mechanism of formation of nanotwins in the high entropy alloy in a short time was illustrated. This study fills in the deformation mechanism and dynamic recrystallization theory of the high entropy alloy, and also provides a new prototype technique for preparation of high entropy alloy with high strength and high ductile properties.

高熵合金是一种应用前景广阔的新型结构材料。纳米孪晶微观结构显著提升了该种材料的强度和韧性。本项目将材料学-动力学-计算机科学相集成，采用3DAP和HADDF-STEM，从原子尺度研究高熵合金剪切带中纳米孪晶的微观特征，探讨间隙元素和原始晶粒尺度等物理冶金因素对于纳米孪晶形成规律的影响，建立高应变率条件下高熵合金孪生变形机制；采用分子动力学模拟高熵合金中纳米孪晶形成过程，建立动力学上可行的高熵合金中晶粒瞬间细化物理模型。从而，诠释高熵合金中纳米孪晶瞬间形成机理。该项研究丰富了高熵合金变形和动态再结晶理论，为制备高强韧高熵合金提供新技术原型和相关理论依据。

高熵合金是一种应用前景广阔的新型结构材料。纳米孪晶微观结构显著提升了该种材料的强度和韧性。本项目将材料学-动力学-计算机科学相集成，采用3DAP和HRTEM，从原子尺度研究高熵合金剪切带中纳米孪晶的微观特征，探讨物理冶金因素对于纳米孪晶形成规律的影响，建立高应变率条件下高熵合金孪生变形机制；模拟高熵合金中纳米孪晶形成过程，建立动力学上可行的高熵合金中晶粒瞬间细化物理模型。从而，诠释高熵合金中纳米孪晶瞬间形成机理。该项研究丰富了高熵合金变形和动态再结晶理论，为制备高强韧高熵合金提供新技术原型和相关理论依据。. 项目完成期间，在SCI收录期刊发表与项目研究内容相关学术论文15篇，在国内一级期刊发表项目研究内容相关学术论文7篇，以主要完成人完成著作1部，授权专利3项，获奖4项，培养博士研究生2人，培养硕士研究生19人。