加张烧成改善连续SiC纤维的束丝拉伸性能

Improved Tensile Behavior of the Continuous SiC Yarns Pyrolyzed from Polycarbosilane under Tension

先驱体法制备连续SiC纤维在烧成过程中有明显的失重和收缩行为,导致纤维在弯曲处应力集中,从而影响其单丝强度和束丝拉伸性能。本工作通过施加一定的张力研究加张烧成方式对连续SiC纤维束丝拉伸性能的影响。结果表明,通过适当的加张,烧成后的纤维平直,丝间平行程度明显改善,束丝断裂负荷显著增加,可编织性明显加强。

Preparation of polymer-derived SiC fibers involves a pyrolysis process, in which great weight loss and shrinkage are usually recorded. As a result, stress concentrates on the bend portion of the fibers and then lower their tensile strength. To avoid the bend portion and stress concentration, a pyrolysis under tension, as well as their effect on the tensile behavior of SiC yarns was studied. Results revealed that so-obtained SiC fibers are straight and parallel to each other. The crack load of SiC yarns is much increased, or in another word, their weave capability is much improved.