(118j) Multi-Scale Metrology for Visualization and Characterization of Interphase Failure

With recent focus on modeling efforts at the micro scale it is important to augment and validate such efforts with experimental efforts at the same scale. This paper will provide a general overview of activities at NIST focused on characterizing the micro scale mechanical properties at the fiber matrix interphase including:

i) Characterization of structure and mechanical properties of interphase
ii) Visualization of interphase failure

The objective of this work is to characterize the structure property relationship of glass fiber composites using recently improved metrology tools at macro and nano scale. The approach to characterize the interface is via interfacial shear strength measurements using single fiber fragmentation and multiple fiber fragmentation test; interphase modulus measurements using AFM; and failure mode visualization using multi-functional molecular probes and advanced fluorescence lifetime imaging microscopy. Due to the complexity of glass fiber sizing systems, model systems were used to investigate interfacial properties and fracture failure modes. It is our belief that creating a mimic to characterize and visualize interface at micro scale is important for validating algorithms for modeling and simulation. Additionally, it aids in fundamental understanding of adhesion and toughening around the interface that is critical for better performance and service life.