孔隙是复合材料的主要缺陷之一,成型过程中孔隙演变的研究对低孔隙率成型T800/802双马树脂碳纤维复合材料制件起到积极作用。采用扫描电镜(SEM)表征了未固化预浸料的断面形貌;自主搭建了在线监测平台,原位观测802双马树脂145℃恒温加热过程中不同时刻气泡的形成与生长;设计了层压板成型断点实验,采用金相表征方法统计5个不同时刻点孔隙率。结果表明:成型前预浸料初始孔隙率为7.81%,成型过程中树脂反应生成气体,气体成核形成孔隙并长大,在压力和树脂状态共同作用下,孔隙经历形成-生长-缩小-稳定过程,孔隙率、孔隙数目和尺寸均先增大后减小。
Pores are one of the main defects of composite materials.The research on the pore evolution during the molding process plays a positive role in the low porosity molding of T800/802 bismaleimide resin carbon fiber composite parts.In this paper,SEM was used to characterize the cross-sectional morphology of uncured prepreg.An in-situ monitoring platform was built independently to observe the formation and growth of bubbles at different times during the heating process of 802 bismaleimide resin at a constant temperature of 145℃.The breakpoint of laminate molding experiment was designed,and the metallographic characterization method was used to count the porosity at five different time points.The results showed that the initial porosity of the prepreg before molding was 7.81%,during the molding process,the resin reacted to generate gas,and the gas nucleated to form pores and grow up.Under the joint action of pressure and resin state,the pores undergo formation-growth-shrinkage-stabilization.During the process,the porosity,pore number and size all increased first and then decreased.
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