Study On Aging Effects Of Typical Space Environments On T700/6421Composite

C scan, electronic balance, AFM, FTIR-ATR and DMA analysis and test methods wereused to in this paper to research aging effects of the environments including80℃/90RHhygrothermal,60℃~180℃vacuum thermal cyclingand220℃high temperatureonT700/6421composites and6421resins, and study the influence which these environmentalfactors lead to on creep and fatigue performance of materials. Environment aging damagemechanism of composites was discussed preliminarily by using macroscopicphenomenological view.The experimental results show that the aging effect of hygrothermal environment ismainly decided by the moisture absorption rate of materials, temperature can accelerate aging.After moisture absorption, the quality of T700/6421composites and6421resins increased,the curve of the hygroscopic rate changing with time square root conforms to Fick’s secondlaw. When moisture reached saturation,6421resins swelled, surface of materials occurreddeformation, the change of glass transition temperature Tgwas not obvious. After moisturedesorption,6421resins swelling disappeared, Tgincreased significantly under temperature.Owing to the influence of interface of T700/6421composites, Tgwas smaller than the originalstate, however, close to the original state after moisture desorption.Vacuum thermal cycling environment aging include vacuum gassing effect and thermalfatigue ageing effect of thermal cycle, which are the direct cause of materials damage. Themass loss rate of T700/6421composites and6421resins along with vacuum thermal cyclingaging meets amendment Fick’s second law double exponential function. After environmentaging, T700/6421composites were affected by the cyclic temperature, the surfacedeformation was observed seriously, Tgincreased.The aging effect of high temperature environment for T700/6421composites and6421resins could be traced to the temperature effect of high temperature and oxidation of theoxygen environment. After high temperature aging, damage of materials was serious, appeared chemical change, surface blacken, cross-link density and Tgincreased. Interface ofT700/6421composites occurred debond, emerged a deep hole in the surface of materials.Relative to the original state, creep performance of6421resins was improved afterhygrothermal and vacuum thermal cycling aging, however fell slightly under hightemperature environment. All of these environments caused T700/6421composite materialsirreversible damage, resulted trend of stiffness decline larger than the original state, fatigueperformance of composites decreased significantly.