The process design of three-dimensional open-die forging and the deformation analysis of metal matrix composites

The rigid-plastic finite element method was used to analyze two new problems of metal forming processes: the process design of open-die block forging and the deformation analysis of unidirectional fiber reinforced metal matrix composites (MMC).; The three-dimensional open die block forging analysis focuses on the effects of die configurations and forging pass designs. Four combinations of die configurations were investigated: conventional flat dies, top flat/bottom V-shaped dies, and double V-shaped dies with 120{dollar}spcirc{dollar} and 135{dollar}spcirc{dollar} included angles. Two different pass designs, 90{dollar}spcirc{dollar} and 180{dollar}spcirc{dollar} rotation angles between succeeding passes, were applied to each die set. The recorded results include the magnitude and distribution of effective strains along the center line of the cylindrical workpiece and the final shape of the workpiece. Good agreement was observed in comparison with experimental data from physical modeling method.; The purpose of the MMC system finite element analyses is to provide the detailed information needed to support a new fabrication method based on forging of preconsolidated MMC plates. Two patterns of fiber arrangement, square and close packed patterns, have been examined by using a two-phase rigid-plastic finite element analysis method and assuming plane strain conditions. Different combinations of friction and number of fibers were tested and the resulting final deformation profiles and required flow stresses were recorded. Based on the analysis, equivalent material models were proposed to simplify the design procedure of MMC systems.; In order to complete the MMC system finite element analysis method, large scale specimens were developed for comparison and identification of fracture criterion. With Tin-Bismuth as the matrix metal and stainless steel wire as the fiber, these specimens were compressed between flat dies, and the results compared with those of the finite element simulations. From this comparison, a fracture criterion based on the magnitude of the effective strain is proposed.