SiC/环氧树脂复合材料冲蚀磨损性能的研究

采用环氧树脂为粘接剂制备了SiC/环氧树脂复合材料,在自制的射流式冲蚀磨损试验机上研究了SiC/环氧树脂的冲蚀磨损性能.结果表明:大尺寸SiC颗粒制备的复合材料较小尺寸SiC颗粒制备的复合材料具有更好的冲蚀磨损性能,且大尺寸SiC颗粒复合材料的冲蚀磨损性能优于Q235钢,而小尺寸SiC颗粒复合材料则低于Q235钢.随着冲蚀角度的变化,其平行材料表面的切削分量和垂直材料表面的冲击分量将会发生变化,低角度冲蚀磨损机理以显微切削和碾压造成环氧树脂及SiC颗粒的层片状脱落为主转变为高角度冲蚀磨损以SiC颗粒碎裂造成环氧树脂疲劳脱落为主.     

熔融渗硅法制备C/C-SiC复合材料的干态摩擦磨损行为及机制

本文以针刺炭纤维整体毡为预制体,采用化学气相渗透法和熔融渗硅法制得炭纤维增强双基体炭/碳化硅(C/C-SiC)摩擦材料;研究了C/C-SiC的干态摩擦磨损行为及机理.研究结果表明:C/C-SiC摩擦材料和30CrMoSiVA合金钢配对摩擦副制动性能稳定,当制动速度从5 000 r/min升至7 500 r/min,摩擦系数由0.33降至0.29,C/C-SiC线磨损率相应由2.01μm/次升至3.40μm/次;C/C-SiC与对偶件的摩擦是犁沟效应和黏着效应共同作用的结果,磨损是磨粒磨损、黏着磨损、氧化磨损和疲劳磨损相互作用的结果.     

Thermoelastic stresses in SiC single crystals grown by the physical vapor transport method

A finite element-based thermoelastic anisotropic stress model for hexagonal silicon carbide polytype is developed for the calculation of thermal stresses in SiC crystals grown by the physical vapor transport method. The composite structure of the growing SiC crystal and graphite lid is considered in the model. The thermal expansion match between the crucible lid and SiC crystal is studied for the first time. The influence of thermal stress on the dislocation density and crystal quality is discussed. The project supported by the National Natural Science Foundation of China (10472126) and the Knowledge Innovation Program of Chinese Academy of Sciences. The English text was polished by Keren Wang