二维非晶纤维/镁合金复合材料强韧性机理研究

Magnesium alloy composites with tailored amorphous microwire structures become a new direction for scientific research, which exhibits enhanced tensile ductility together with higher strength. A new experiment means of observation in situ by use of scanning electron microscope with a tensile stage and digital scattering correlation method is put forward to develop the mechanisms of amorphous microwires improving strength-toughness properties of magnesium alloy composites. In this project, a CoFeSiB two-dimensional metallic glass microwire structure will be developed by weaving and braze welding methods. A MgZnNdZr alloy composite with uniform two-dimensional amorphous microwire structures will be prepared by semi-solid extruding techniques. Their microstructures and interface adhesion mechanisms will be investigated by advanced analytical techniques. The plastic deformation behaviors and fracture mechanisms of magnesium alloy composites with two-dimensional amorphous microwire structures will be examined in situ by means of scanning electron microscope with a tensile stage under quasi-static tension loading mode. The relationship of the feature of amorphous microwire structures and plasticity deformation and fracture strength will be clarified. The elastic deformation behavior and the stress transport between the amorphous microwire and the magnesium alloy matrix will be studied by using digital scattering correlation method. The strain and stress transfer mechanisms between the amorphous microwire and the magnesium alloy matrix will be studied. This project will provide a better understanding of the mechanisms of amorphous microwires improving strength-toughness properties of magnesium alloy composites. It will be expected that this study will lay the solid foundation for the exploration of magnesium alloy composites with high strength-toughness capacity.

具有显著拉伸塑性及高强度非晶纤维/镁合金复合材料是一新科学研究方向。提出使用数字散斑相关法及扫描电镜原位观测新手段，探究非晶纤维提高镁合金强韧性机理。使用编织及钎焊方法制备CoFeSiB二维非晶纤维结构，使用半固态挤压技术制备含二维非晶纤维结构的MgZnNdZr合金复合材料，应用先进分析技术研究其微观结构及界面结合机制。设计扫描电镜原位观测准静态单轴拉伸实验，研究含二维非晶纤维结构镁合金复合材料塑性变形及断裂机制，建立非晶纤维特征与塑性变形及断裂强度关系。使用数字散斑相关法原位观测复合材料弹性变形及非晶纤维与镁合金间应力传输。研究非晶纤维与基体间应力和应变转换机制。深入认识非晶纤维提高镁合金复合材料强韧性机理，为设计及开发高强韧镁合金复合材料提供理论指导。