Patent ID: 8613818

Claim:
A method of refining a grain size of a workpiece comprising a metallic material selected from titanium and a titanium alloy, the method comprising: heating the workpiece to a workpiece forging temperature within an alpha+beta phase field of the metallic material; and multi-axis forging the workpiece, wherein multi-axis forging comprises press forging the workpiece at the workpiece forging temperature in the direction of a first orthogonal axis of the workpiece with a strain rate sufficient to adiabatically heat an internal region of the workpiece, allowing the adiabatically heated internal region of the workpiece to cool to the workpiece forging temperature, while heating an outer surface region of the workpiece to the workpiece forging temperature, press forging the workpiece at the workpiece forging temperature in the direction of a second orthogonal axis of the workpiece with a strain rate that is sufficient to adiabatically heat the internal region of the workpiece, allowing the adiabatically heated internal region of the workpiece to cool to the workpiece forging temperature, while heating the outer surface region of the workpiece to the workpiece forging temperature, press forging the workpiece at the workpiece forging temperature in the direction of a third orthogonal axis of the workpiece with a strain rate that is sufficient to adiabatically heat the internal region of the workpiece, allowing the adiabatically heated internal region of the workpiece to cool to the workpiece forging temperature, while heating the outer surface region of the workpiece to the workpiece forging temperature, and repeating at least one of the preceding press forging and the allowing steps until a true strain of at least 3.5 is achieved in at least a region of the workpiece.