Fiber bias in nanoindentation of polymer matrix composites

Abstract Nanoindentations were performed in the near fiber region of the matrix of a polymer matrix composite to attempt to determine the nanomechanical properties of the interphase. A possible fiber bias effect was observed and this effect was confirmed by performing nanoindentations in both the presence and in the absence of fiber. Changes in experimentation by using lower loads (40 μN and 80 μN) reduced the fiber bias effect. Cutting the samples at an angle to the fiber axis was performed to try to further reduce the fiber bias effect. The experimental variations considerably reduced the fiber bias effect. Specifically, the combination of angled cutting and use of reduced loads eliminated the fiber bias effect at distances greater than 150 nm from the fiber. Keywords: INTERPHASEPOLYMER MATRIX COMPOSITESNANOINDENTATIONFIBER BIAS EFFECT