An investigation into the forming limits of sintered porous materials under different operational conditions

This study is to investigate the forgeability of sintered porous materials under various operational conditions, including the aspect ratio (the height-to-diameter ratio) of billets, the void volume fraction, and the frictional conditions during the deformation. Experiments and finite element analysis were conducted to examine the process. The material properties of sintered preforms were ascertained from both the uni-axial tension and compression test. The finite element models were verified with the upsetting experiments under different frictional conditions. A new forming limit criterion for porous metals was formulated. Studies show that the aspect ratio bears a directly proportional relation to the fracture strain. The increase of voids deteriorates the strength and reduces the forging limits. Higher friction makes it easier to incur cracks in the workpiece and hence inhibits the workability.