Use of Forming Limit Criteria in Forging Complex Shapes From Metal-Matrix Composites

Fundamental deformation and fracture behavior of fiber-reinforced metal-matrix composites under deformation processing conditions were determined using upset tests on rectangular specimens. Defects that occur during simulated forging of a 2024 Al-alloy matrix reinforced with 25v/o stainless steel wires were characterized, and forming limit criteria for their prediction and prevention established. These criteria, determining the limits of deformation, provided guidelines for development of a process for forging an airfoil shape from the composite system studied. To this end, the limiting criteria were combined with an analysis of the flow of metal during forging. The forging design method developed, based on the forming limit criteria, demonstrates a rational approach to the design of processes for forging complex shapes from composite materials. Utilizing this approach, process parameters (die and preform geometry, lubrication) can be evaluated for forging sound complex composite shapes.