If you have ever run a SOLIDWORKS Simulation
study with a large number of parts you will be aware that it can take a little time to assign the correct materials to each part.
A useful, but often overooked, technique is to drag/copy materials from one part to the next - within the Parts folder. All you do is select the part (or body) with the material you want to copy and drag it to another part. You don't even have to press CTRL! A yellow symbol appears that shows the destination part.
Here is a screenshot that shows a Plain Carbon Steel material being copied onto another part ...