多孔SiC陶瓷/Zr基非晶合金复合材料动态压缩性能研究

Dynamic Compressive Properties of Porous SiC Ceramic/Zr-Based Amorphous Composites

通过压力-浸渗法制备多孔SiC陶瓷/Zr基非晶合金复合材料。利用分离式霍普金森压杆装置(SHPB)、S-4800场发射扫描电镜等测试分析手段,探究复合材料制备保温时间和多孔碳化硅性能对多孔SiC陶瓷/Zr基非晶合金复合材料动态压缩性能的影响,并揭示了其变形机制。结果表明:保温时间和多孔碳化硅性能对多孔SiC陶瓷/Zr基非晶合金复合材料的动态抗压强度都有较大影响,当多孔碳化硅孔隙率为23.77%,平均孔径尺寸为26.72μm时,在复合材料制备浸渗温度为860℃,浸渗后保温6.0 min时,复合材料具有最高的动态抗压强度,为1757 MPa。多孔SiC陶瓷/Zr基非晶合金复合材料动态压缩断裂为脆性断裂,断口微观形貌特征包括SiC陶瓷相上形成具有不同特征的解理台阶,Zr基非晶合金相形成不同形态的脉状花样,非晶相保持相对完整。Zr基非晶合金相能有效阻碍裂纹的扩展,导致非晶相周围的碳化硅碎裂并挤压非晶相整体运动,从而提高了多孔SiC陶瓷/Zr基非晶合金复合材料动态抗压强度。

The porous SiC ceramics/Zr-based amorphous alloy composites were prepared by the pressure-infiltration casting method.The influence of pressure-infiltration casting holding time and the properties of porous SiC ceramics on the dynamic compression performance were investigated with the split Hopkinson pressure bar(SHPB) and the S-4800 scanning electronic microscope(SEM).The results show that the dynamic compressive strength of porous SiC ceramic/Zr based amorphous alloy composites is significantly affected by the holding time and the properties of porous SiC ceramic.The composites exhibit the highest dynamic compressive strength which is 1757 MPa with the porosity and average aperture size at 23.77% and 26.72μm,respectively,at the pressure-infiltration casting temperature of 860℃ for 6.0 min.The fracture mode of the composite shows the brittle fracture under the dynamic compress load.The fracture morphology characteristics include the cleavage steps with different characteristics appearing in ceramic,different patterns of veins formed in Zr-base amorphous alloy,and the amorphous being kept in a relatively intact state.The Zr-based amorphous alloy can effectively hinder cracks expansion,resulting in the surrounding silicon carbide fracture and pushing movement of the amorphous phase;thus it would improve the dynamic compressive strength of porous SiC ceramic/Zr-based amorphous composites.