Kevlar纤维缝纫泡沫芯材复合材料力学性能研究

Mechanical properties of kevlar fiber stitched foam core composite sandwich plates

基于热压罐成型工艺,制备了kevlar纤维缝纫泡沫芯材复合材料夹层板,并通过扫描电镜观察了胶膜中的树脂在kevlar纤维束之间的浸润状态,为工程化应用提供参考.选取未缝纫泡沫夹芯复合材料和碳纤维预浸料缝线缝纫泡沫芯材复合材料夹层板为对比试样,实验研究了kevlar纤维缝纫泡沫芯材复合材料夹层板的平压、剪切和侧压力学性能,并考察了缝纫针距、行距的变化对其力学性能和破坏模式的影响.研究表明:在真空压力下,胶膜中的树脂与kevlar纤维浸润良好;对泡沫芯材进行kevlar纤维缝纫增强后,其力学性能显著提高,并改变了夹层板的破坏机理.实验范围内,随着缝纫密度的提高,平压强度和模量增大;夹层板剪切性能和侧压性能受缝纫密度的影响较大,在缝纫参数(缝纫行距×针距)为10 mm×10 mm时,增强效果较佳,其剪切强度和侧压强度分别提高了44%和21%,剪切模量和侧压模量分别提高了34%和127%.

Spraying precursor（6wt.%Al2O3-7wt.%YSZ mixed powder） was processed by vibration mill,and then characterized with XRD and TEM.The grinded precursor and 7wt.%YSZ powder were sprayed by using the atmospheric plasma spraying equipment to fabricate the AYSZ and YSZ coatings.SEM,XRD and EDS were applied to study the microstructure and the phase composition of both coatings.The results revealed that AYSZ droplets produced lots of defects of strain and dislocation after vibration milling,making the material in metastable and high-energy active state.Material internal stored energy was released under the condition of high temperature plasma.As a result,the AYSZ coating columnar grain size was reduced to the nanometer level.Compared to YSZ coating,AYSZ coating contains a lot of c-ZrO2 which improves the porosity,elastic modulus and hardness.