In a Medieval setting, how much would a sickle shape increase the impact area?

In basically every medieval depiction of a battle-axe, the axe will have a sickle shape on the end. I also know that sickle shapes have a long history in even earlier weapons. <br><br>I’m just wondering about the benefit of having a sickle shape on such a weapon. Let’s assume that a weapon would have somewhere between 10-40 pounds (4.5-18 kilos) of force behind each swing. Would, say, a 2 inch (5 centimeter) curve on the end of the weapon increase how much of the force is distributed through the swing?