Alien Zombie War Machines (1st in the "Related to The Knife" books)

Captain Alice Jackson's battleship, The Valkyrie, is badly damaged in battle. The ship takes the longest warp-jump humans have ever tried and finds itself 40,000 years in the past on the far side of the galaxy. There, mindless Zombie War Machines are taking over civilizations. Now they want to follow The Valkyrie home. Captain Jackson knows her ship and crew must never allow that horror to happen, at any cost.