CRCU

Chemical Research in Chinese Universities ›› 2018, Vol. 34 ›› Issue (3): 451-456.doi: 10.1007/s40242-018-7430-9

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Effect of Thermal Cycles on the Thermal Expansion Behavior of T700 Carbon Fiber Bundles

GENG Guoliang1, MA Xiaofei2, GENG Hongbin1, WU Yiyong1   

  1. 1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China;
    2. CAST-Xi'an Institute of Space Radio Technology, Xi'an 710100, P. R. China
  • Received:2017-12-28 Revised:2018-01-12 Online:2018-06-01 Published:2018-02-28
  • Contact: GENG Guoliang, MA Xiaofei E-mail:Maxf041600@sina.com;12B309012@hit.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.U1537213).

Abstract: The relationships between the coefficient of thermal expansion(CTE) of T700 carbon fiber bundles(CFBs) and the thermal cycles were investigated. The microstructure of T700 CFBs was analyzed with Raman spectra and XRD before and after the thermomechanical test. The results indicated that the T700 CFBs exhibited negative expansion in the direction of parallel fibers in the temperature range of -150-150℃. The thermal strain that occurred during the heating and the cooling thermal cycle had an unclosed curve that served as the loop. When the experimental load was the same, the position of strain loop tended to move upward, and the length of the specimen increased continuously with the thermal cycles increasing. The microstructural analysis suggested that the degree of structural order and the degree of orientation along the fiber axis were improved with the increase of thermal cycles. The change of microstructure parameters could be the primary cause of the negative CTE's variation within the T700 CFBs.

Key words: T700 carbon fiber bundle, Thermal cycle, Coefficient of thermal expansion, Microstructural analysis