PTFE/Kevlar纤维编织材料摩擦损伤演变规律研究

目的 通过对PTFE/Kevlar纤维编织材料进行不同循环次数的往复摩擦磨损试验,研究并揭示其摩擦损伤演变规律和损伤机理.方法 采用MXW-5型摩擦磨损试验机,同时保持一定的位移和频率,对材料分别进行2、5、10 N等3种载荷等级下往复运动的不同循环次数试验.采用体视显微镜(SM)对材料磨损表面在试验过程中产生的宏观损伤进行分析,利用3D光学显微镜(3D-OM)、扫描电子显微镜(SEM)、X射线能谱仪(EDS)对损伤表面的微观形貌以及化学状态加以分析.结果 3种不同载荷条件下的样品,在达到1000次循环往复运动之前,摩擦因数增大0.05,1000～5000次增幅减缓为0.02,并逐渐趋于稳定.不同循环次数下,损伤表面形成了不同大小的PTFE转移膜,将表面C元素覆盖.3种载荷下,编织材料的磨损机制主要为疲劳磨损.结论 在载荷不变的条件下,随着循环次数的增加,前期编织材料磨痕表面部分区域会形成PTFE转移膜,对Kevlar纤维产生一定的保护作用,进而降低表面磨损程度.随着表面磨损程度不断加剧,磨痕表面形成的PTFE转移膜剥落,导致纤维重新暴露在表面,使磨损进一步加剧.同时,随着材料样品磨损不断严重,磨痕表面的氧化程度不断加深.

Evolution of Frictional Damage of PTFE/Kevlar Fiber Braided Materials

The purpose of this paper is to study and reveal the frictional damage evolution law and damage mechanism of the PTFE/Kevlar fiber braided material via reciprocating friction and wear tests with different cycles. Using the MXW-5 friction and wear testing machine, while keeping the displacement and frequency of the movement constant, the materials were tested with different cycles of reciprocating motion under three load levels of 2 N, 5 N, and 10 N. A stereo microscope (SM) is used to analyze the macroscopic damage of the worn surface of the material after the test. The microscopic morphology and chemical state are analyzed with 3D optical microscope (3D-OM), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometer (EDS). The friction coefficient of the samples under three different loading conditions increased by 0.05 before reaching 1000 cycles of reciprocating motion, and the increase rate slowed down to 0.02 from 1000 to 5000 times and gradually stabilized. Under different cycles, the damaged surface formed a PTFF transfer film in different sizes covered the C of worn surface. The main wear mechanism of braided materials under three loads is fatigue wear. Under the condition of constant load, as the number of cycles increases, the PTFE transfer film will be formed on the worn surface in the early stage, which will protect the Kevlar fiber to a certain extent, thereby reducing the degree of surface wear. As the degree of surface wear continues to intensify, the transfer film formed on the surface of the wear scar is peeled off, causing the fibers to be exposed to the surface again, which further intensifies the wear. At the same time, as the wear of material samples intensified, the degree of oxidation on the surface of the wear scars continued to deepen.