Considering the significant power that the Elder Wand has, it seems unlikely that a seventeen year old boy would be able to break it in half by force. But why does Harry break the Elder Wand without repairing his own wand? It's understandable that he doesn't want a part of the Deathly Hallows to exist for fear of another wizard rising to the same power that Voldemort was trying to achieve, so why not destroy it after he's fixed his wand that was broken? And at least keep the two pieces to dedicate to a museum that surely would have been erected about Voldemort's rise to power and Harry and Dumbledore's defeat over the Dark Lord.
