Abstract The in-situ quantitative characterization of the interface structure and properties of carbon fiber/epoxy resin composites was carried out by using peak force quantitative nanomechanical mapping (PF-QNM) technology in this study. The mechanism of hygrothermal damage was developed. It is found that the hygrothermal aging can be divided into three stages. In the first stage, the resin matrix and the interface absorb simultaneously moisture and the interface size increases linearly from 45.2±4.1 nm to 76.2±10.3 nm. The increase of the "soft interface" area makes the bending strength and interlaminar shear strength decrease by 17.3% and 15.8%, respectively. In the second stage, resin matrix undergoes secondary curing and the interface size continues to increase up to 110.8±13.8 nm, resulting in the increase of the bending strength, interlaminar shear strength and impact resistance. The impact peak load and strain energy increase by 56.1% and 1286.3%, respectively. In the third stage, interface area is saturated with moisture and the size changes little and the resin continues to absorb moisture, resulting in the swells and plasticization under high temperature and high humidity. The bending strength and interlaminar shear strength of the material decrease respectively to 1185.9±13.1 MPa and 53.2±3.2 MPa, with a reduction of 27.6% and 28.0%.

中文翻译：

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基于界面结构定量表征的碳纤维/环氧树脂复合材料湿热老化机制

摘要 本研究利用峰值力定量纳米力学映射(PF-QNM)技术对碳纤维/环氧树脂复合材料的界面结构和性能进行了原位定量表征。开发了湿热损伤的机制。发现湿热老化可分为三个阶段。在第一阶段，树脂基体和界面同时吸收水分，界面尺寸从 45.2±4.1 nm 线性增加到 76.2±10.3 nm。“软界面”面积的增加使弯曲强度和层间剪切强度分别下降17.3%和15.8%。在第二阶段，树脂基体进行二次固化，界面尺寸不断增加，达到 110.8±13.8 nm，导致弯曲强度增加，层间剪切强度和抗冲击性。冲击峰值载荷和应变能分别增加了 56.1% 和 1286.3%。第三阶段，界面区域水分饱和，尺寸变化不大，树脂继续吸潮，在高温高湿下发生溶胀塑化。材料的弯曲强度和层间剪切强度分别下降到1185.9±13.1 MPa和53.2±3.2 MPa，下降27.6%和28.0%。导致在高温高湿下溶胀塑化。材料的弯曲强度和层间剪切强度分别下降到1185.9±13.1 MPa和53.2±3.2 MPa，下降27.6%和28.0%。导致在高温高湿下溶胀塑化。材料的弯曲强度和层间剪切强度分别下降到1185.9±13.1 MPa和53.2±3.2 MPa，下降27.6%和28.0%。