Li Shaolin, Qi Lehua, Zhang Ting, Ju Luyan, Li Hejun
State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an, 710072, PR China.
State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an, 710072, PR China; School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, 710072, PR China.
Micron. 2017 Oct;101:170-176. doi: 10.1016/j.micron.2017.07.004. Epub 2017 Jul 12.
In spite of the effectiveness of the fiber coatings on interface modification of carbon fiber reinforced magnesium matrix composites, the cost and exclusive equipment for the coatings preparation are usually ignored during research work. In this paper, pyrolytic carbon (PyC) and TiO were coated on carbon fiber surface to study the effects of fiber coatings on interfacial microstructure and mechanical properties of carbon fiber reinforced AZ91D composites (C/AZ91D composites). It was indicated that both the two coatings could modify the interface and improve the mechanical properties of the composites. The ultimate tensile strength of the TiO-C/AZ91D and the PyC-C/AZ91D composite were 333MPa and 400MPa, which were improved by 41.7% and 70.2% respectively, compared with the untreated-C/AZ91D composite. The microstructure observation revealed that the strengthening of the composites relied on fiber integrity and moderate interfacial bonding. MgO nano-particles were generated at the interface due to the reaction of TiO with Mg in the TiO-C/AZ91D composite. The volume expansion resulting from the reaction let to disordered intergranular films and crystal defects at the interface. The fibers were protected and the interfacial reaction was restrained by PyC coating in the PyC-C/AZ91D composite. The principle to select the coating of fiber was proposed by comparing the effectiveness and cost of the coatings.
尽管纤维涂层在碳纤维增强镁基复合材料的界面改性方面具有有效性，但在研究工作中，涂层制备的成本和专用设备通常被忽视。本文在碳纤维表面涂覆热解碳（PyC）和TiO，以研究纤维涂层对碳纤维增强AZ91D复合材料（C/AZ91D复合材料）界面微观结构和力学性能的影响。结果表明，两种涂层均可改善界面并提高复合材料的力学性能。TiO-C/AZ91D复合材料和PyC-C/AZ91D复合材料的极限抗拉强度分别为333MPa和400MPa，与未处理的C/AZ91D复合材料相比，分别提高了41.7%和70.2%。微观结构观察表明，复合材料的强化依赖于纤维完整性和适度的界面结合。在TiO-C/AZ91D复合材料中，由于TiO与Mg反应，在界面处生成了MgO纳米颗粒。反应产生的体积膨胀导致界面处晶间薄膜无序和晶体缺陷。在PyC-C/AZ91D复合材料中，PyC涂层保护了纤维并抑制了界面反应。通过比较涂层的有效性和成本，提出了选择纤维涂层的原则。
