Ti基非晶合金及其SiC陶瓷骨架复合材料动态压缩力学行为研究

为了验证Ti基非晶合金和陶瓷两种材料三维连通网状结构的复合优势，制备出具有优良抗冲击性能的复合材料，本文采用铜模吸铸法制备了Ti基非晶合金，并用渗流铸造法制备出孔隙率分别为30.86%、18.14%和15.28%的Ti基非晶合金/SiC陶瓷骨架复合材料。采用X射线衍射仪对纯Ti基非晶合金以及SiC陶瓷骨架复合材料进行相分析，确认了试件材料的非晶状态；在不同应变速率下，用分离式霍普金森压杆(SHPB)实验装置对试样进行室温轴向动态压缩力学性能测试，并利用能谱型场发射扫描电镜(SEM)等设备观察了试件的微观组织和断面特征，对比分析了Ti基非晶合金和SiC陶瓷骨架复合材料的动态压缩力学性能和失效机理。研究表明，Ti基非晶合金/SiC陶瓷骨架复合材料内部的微裂纹最初萌生于应力集中的两相界面处，并在SiC相内部或两相界面处扩展，继续加载，SiC相失效后，Ti基非晶合金相在远超过其动态压缩强度的应力下迅速失效，复合材料整体失效。SiC相内的断裂形貌主要有微裂纹与解理台阶，Ti基非晶合金相内的断裂形貌有脉状花样、多重脊状条带、蜂窝状花样与光滑无特征区，其中以光滑无特征区为主。复合材料的抗压强度随Si...

Dynamic compressive mechanical behaviors of Ti-based amorphous alloy and SiC ceramic framework composites

In order to verify the composite strengths of Ti-based amorphous alloy and ceramics with three-dimensional connected mesh structure and prepare composites with excellent impact resistance, Ti-based amorphous alloy was prepared by copper mold suction casting method, and Ti-based amorphous alloy/SiC ceramic framework composites with porosity of 30.86%, 18.14%, and 15.28% were prepared by infiltration casting method. The metallographic structure analysis of pure Ti-based amorphous alloy and SiC ceramic framework composites was performed using X-ray diffractometer, which verified the amorphous state of the specimens. Under different strain rates, the mechanical properties of the specimens were tested under axial dynamic compression at room temperature using split Hopkinson pressure bar (SHPB) experimental device, and the microstructure and cross-sectional characteristics of the specimens were observed by spectral field emission scanning electron microscopy (SEM). The dynamic compressive mechanical properties and failure mechanisms of Ti-based amorphous alloy and SiC ceramic framework composites were compared and analyzed. Results show that the microcracks inside the Ti-based amorphous alloy/SiC ceramic framework composites initiated at the interface between the two metallographic structure where the stress was concentrated and then expanded inside the SiC metallographic structure or at the interface between the two metallographic structure; with further loading, after the failure of the SiC metallographic structure, the Ti-based amorphous alloy metallographic structure failed rapidly under the stress far exceeding its dynamic compressive strength, and the composite failed entirely. The fracture morphology in the SiC metallographic structure mainly consisted of microcracks and cleavage steps, while that in the Ti-based amorphous alloy metallographic structure consisted of vein-like patterns, multiple ridged bands, honeycomb-like patterns, and smooth featureless areas, among which the smooth featureless areas were dominant. The compressive strength of the composites increased with the increase in SiC content, and the dynamic compressive strength of the composites with SiC volume fraction of 85% reached 1 664 MPa.