Split pass forging a workpiece to initiate microstructure refinement comprises press forging a metallic material workpiece in a first forging direction one or more times up to a reduction ductility limit of the metallic material to impart a total strain in the first forging direction sufficient to initiate microstructure refinement; rotating the workpiece; open die press forging the workpiece in a second forging direction one or more times up to the reduction ductility limit to impart a total strain in the second forging direction to initiate microstructure refinement; and repeating rotating and open die press forging in a third and, optionally, one or more additional directions until a total amount of strain to initiate microstructure refinement is imparted in an entire volume of the workpiece.