摘要
目的以短切碳纤维增强尼龙6复合材料(CF/PA6)为研究对象,系统探究了预浸料片材长宽比对其力学性能的影响规律,进而提出了一种短切预浸料片材的尺度优选方法。方法制备了4种长宽比(1∶1、2∶1、4∶1、6∶1)的短切CF/PA6预浸料片材,通过排气辅助模压成型工艺制备出力学性能测试样件,利用光学显微镜与显微CT定量表征微观孔隙与纤维面外波纹缺陷,并结合拉伸实验分析片材尺度对宏观力学性能的影响。结果随片材长宽比的增大,材料内部孔隙分布均匀性下降,大尺寸(≥10^(15) nm^(3))孔隙数量增多,同时纤维面外波纹显著加剧,平均波纹比与波纹角分别提高了122%与140%。拉伸性能与模量均随着长宽比的增大呈现先升后降的趋势,并于2∶1时达到最优值。结论短切预浸料片材长宽比通过影响微观缺陷的演化与应力传递结构的连续性来影响复合材料力学性能。当长宽比为2∶1时,可实现纤维应力传递效率与缺陷抑制的有效平衡,为其在复杂结构件中的性能优化与工艺设计提供了重要依据。
The work aims to investigate chopped carbon fiber reinforced polyamide 6(CF/PA6)composites to systematically examine the effect of sheet aspect ratio on mechanical properties,so as to propose an optimal selection methodology for prepreg sheet dimensions.Four types of CF/PA6 sheets with aspect ratios of 1∶1,2∶1,4∶1,and 6∶1 were prepared.Test specimens were fabricated through an exhaust-assisted compression molding process.Microstructural defects such as pores and out-of-plane fiber waviness were quantitatively characterized with optical microscopy and micro-CT,while tensile tests were conducted to evaluate macro-mechanical properties.With the increasing aspect ratio,the uniformity of pore distribution decreased,and the number of large pores(≥10^(15) nm^(3))increased.Meanwhile,out-of-plane fiber waviness became more severe,with the average waviness ratio and waviness angle increasing by 122%and 140%,respectively.Both tensile strength and modulus initially increased and then decreased as the aspect ratio increased,peaking at an aspect ratio of 2∶1.The aspect ratio of chopped prepreg sheets affects the mechanical properties of composites by influencing the evolution of microscopic defects and the continuity of stress transfer pathways.An aspect ratio of 2∶1 achieves an optimal balance between efficient stress transmission and defect suppression,providing critical insight for performance optimization and process design of complex structural components.
作者
刘粤海
付饶
严洪彬
王琦
马赛
王福吉
LIU Yuehai;FU Rao;YAN Hongbin;WANG Qi;MA Sai;WANG Fuji(State Key Laboratory of High-Performance Precision Manufacturing,Dalian University of Technology,Liaoning Dalian 116024,China;Key Laboratory of High-Performance Manufacturing for Advanced Composite Materials,Liaoning Province,Dalian University of Technology,Liaoning Dalian 116024,China;Liaoning Huanghai Laboratory,Dalian University of Technology,Liaoning Dalian 116024,China)
出处
《精密成形工程》
北大核心
2025年第11期58-67,共10页
Journal of Netshape Forming Engineering
基金
国家自然科学基金(52090053)。
