Chris;
If you mean does the material compress as you drive it (actually, with blind rivets you pull the stems up into the body)- yes, a little, but the rivet pulls the two sheets together and expands as the stem is pulled. In addition, there is a bulge formed behind the last sheet that keeps the rivet body from falling out. Aerospace rivets also lock the stem into place so that vibration doesn't shake it out of the body.
Drilling a nice clean round hole of the proper size is important as well as using the proper "grip length" for the thickness of the material. It takes too much pulling force to use a hand tool when you are using 5/32" Monel body & 15-7 PH stem rivets. I have to use my FSI "pneudraulic" gun for these types.
Using temporary fasteners such as Clecos is a must to keep all the holes aligned when they are drilled and again when they are riveted. Without Clecos, it's guaranteed that after a few holes, the panels walk off and the other holes don't line up.
Regards, Neil Tucson, AZ