Creep and Physical Aging in a Polyamideimide-Carbon Fiber Composite.

摘要

The creep properties of an amorphous thermoplastic polyamideimide and it's continuous carbon fiber composite have been investigated. Creep behavior in the viscoelastic (low stress) and viscoplastic (high stress) ranges was examined. The interaction of physical aging with the creep behavior of the material was found to be significant in both stress regimes. Physical aging shifted creep curves to longer times in the viscoelastic range, reducing the total amount of creep strain in both the viscoelastic ranges. The amount of non-recoverable strain produced during viscoplastic creep was highly dependent upon the amount of time a sample was held under load due to concurrent physical aging. Specimens aged significantly prior to testing showed no undue time dependence in the amount on non-recoverable creep strain produced. The viscoplastic creep behavior was shown to be composed of instantaneous localized plastic deformation, viscous strain, stiffening due to aging, and densification due to aging.