This video shows the damage done to the edges of sharp replica European Longswords when they are hit against each other edge-on-edge.
The swings were not full force and the standing targets were not rigidly held in place, thus significantly reducing the amount of impact. Despite such reductions of force, the incredible amounts of damage can be seen. The gouges and gashes done to the edges would have been extremely difficult, if not impossible, to repair in the Medieval and Renaissance times.
As a result of tests such as these, it has been strongly argued that one should receive blows with the flat of the blade and not the edge. The flex of the blades will absorb a significant amount of impact, thus greatly reducing the damage done to the blades, and the force is distributed over a much larger area when an edge hits a flat.
Note: The swords used in the test were already unusable for normal training, so don't fret ;)