3-D Microstructural Interface Characterization with In-situ X-Ray Micro-Computed Tomography Tensile Loading

Interfaces play a critical role in the resulting mechanical performance and failure mechanisms of composite materials; however, interface characterization can be challenging. This report summarizes an X-ray micro-computed tomography technique to quantitatively measure cavities between glass particles and a polyurea matrix during in-situ tensile loading. This material is a mock surrogate for energetic materials of interest with similar interfacial chemistry, particle loading, and size distribution. We believe the fundamental failure mechanisms will apply to similar energetic composites. Our work investigated glass particles with and without a silane coating scanned at both a low and high loading strain. Subsequent analysis quantified the number and magnitude of cavity separations, their volume, and the volume of each cavity's respective glass sphere. Results showed the coated particles had less frequent separations compared to the uncoated particles at both the low and high tensile strains. Unexpectedly, there was not a preferential cavity formation initiating on the larger glass volumes when comparing the cavity sizes to their respective glass sphere sizes. This experimental technique offers a unique opportunity to assess 3-D cavity formation and growth in particle-filled composite materials, which can provide an increased fundamental understanding of a composite interfaces role during failure.