A cyclic indentation test was carried out on PR520 epoxy resin and its 3D interlock carbon fiber reinforced composite in order to study the effects of thermo-oxidative aging on the material local properties. Thermal aging has been performed in air at 150 °C, which is close to the service temperature in warm zones of aircrafts, for different durations. Two parameters have been considered in this study: the reload indentation modulus, representative of the elastic response, and the ratio between irreversible and total indentation energy, representative of plastic (first cycle) and viscoelastic response. The analysis of cyclic indentation curves shows that elastic and plastic behavior are affected by thermal aging, while viscoelastic behavior is not. Moreover, a gradient of local properties has been measured through the thickness of aged samples. The affected zone extends of about 150 µm from the surface exposed to the oxidative environment, while the properties of the sample core are similar to those of the virgin material. Property gradient profiles measured on resin and composite aged in the same conditions are well superposed.

为了研究热氧化老化对材料局部性能的影响，对 PR520 环氧树脂及其 3D 互锁碳纤维增强复合材料进行了循环压痕试验。热老化在150°C的空气中进行了不同的持续时间，接近飞机温暖区的使用温度。本研究中考虑了两个参数：重新加载压痕模量，代表弹性响应，以及不可逆和总压痕能量之间的比率，代表塑性（第一次循环）和粘弹性响应。循环压痕曲线分析表明，弹性和塑性行为受热老化影响，而粘弹性行为则不受。此外，通过老化样品的厚度测量了局部特性的梯度。受影响的区域从暴露于氧化环境的表面延伸约 150 µm，而样品核心的特性与原始材料的特性相似。在相同条件下老化的树脂和复合材料的性能梯度曲线很好地叠加。