I'd suggest using the particle analysis tools in the free software ImageJ.

https://imagej.net/Particle_Analysis

https://imagej.nih.gov/ij/docs/pdfs/examples.pdf

U can use dissolution technique to analyze the vol. fraction of the reinforcement.

Refer: https://link.springer.com/article/10.1007/s11665-019-03992-6

you can used analytical modelling.

Read : Sisal fibril epoxy composite-a high strength electrical insulating material

Dear Sir, You could use the following online tool, to calculate the volume and weight fractions of the reinforcements: https://netcomposites.com/guide-tools/tools/calculators/volume-weight-fraction/

Here, we have to mention the density of the reinforcements (fiber) and the density of matrix (resin) to find the volume fraction.

Dear Ali Tozar ,

The best solution that you have is using ImageJ/fiji software, but instead if you don't have any access to that, also you can use ASTM standard number E562,

best wishes,

Nemat.

Thank you for all the valuable suggestions. All of them are proper methods.

What do you think about converting the atomic percentage (obtained by eds) to weight percentage and then to volume percentage?