Microstructural characterization and mechanical property prediction of a polymer matrix composite by X-ray synchrotron tomography and spatial correlation functions

Polymer matrix composites have become increasingly popular due to their ability of achieving high stiffness and strength without sacrificing desirable ductility. In the present work, we investigate the mechanical properties of borosilicate glass spheres reinforced polypropylene matrix composites with varying volume fractions of the glass spheres, using both tensile tests and nanoindentation measurements. The objective was to study the effect of volume fraction of borosilicate glass spheres on the mechanical behavior of the overall composite system. During the tensile test, the strain in the sample was calculated through three different methods: extensometer measurement, digital image correlation and image processing. The results from these three methods were discussed and compared. X-ray tomography was used for 3D characterization of the microstructure and to investigate failure mechanisms. Additionally, we also developed and validated a systematic procedure for predicting mechanical properties of the composite system by using constituent properties of individual phases coupled with microstructural information obtained from X-ray tomography, quantified via spatial correlation functions. This part of the study focuses on using minimum number of slices to predict mechanical properties, and this is very crucial as handling large 3D datasets is very complicated and time-consuming.