When Loki conquered all of the eight realms except for Midgard, Alfheim was among them. Its ruler, Lord Fray of Vanaheim, had fallen in battle against Loki's forces and the Light Elf army went into disarray and scattered in their realm trying to evade capture and death from Loki.
Hawkeye had been pulled to Alfheim because of the Norm Stones he and his teammates destroyed. He met Faradei as he hitch hike on his steed running from Loki's hounds until rescued by Black Panther, who already found his way out from the Dark Elves' realm.
After Loki's defeat by the Avengers, all of the conquered realms became free, including Alfheim.