FORGING/FORMING SIMULATION STUDIES ON A UNIQUE, HIGH CAPACITY DEFORMATION SIMULATOR APPARATUS

Abstract

Unique forging simulation equipment exists at CWRU that combines high load capacity (i.e., 110/220 kip) and the ability to test “large” specimens. In addition, loading rates, which span industrially relevant ranges (i.e., 0.004–120 in./sec) and the ability to provide single or multiple deformation sequences at desired strain levels/loading rates are possible, with data acquisition (e.g., load, displacement) at rates sufficient to capture the load history during the single/multiple deformation sequences. A description of the equipment capabilities and examples of preliminary work on a range of materials, including monolithic Al alloys, polypropylene, and both fully dense and porous P/M aluminum composites is given. Tests conducted on the polypropylene revealed that flow stress is a function of strain rate and increases with increasing strain rate. In addition, extensive damage was detected after forging in all of the polypropylene specimens. It was found that flow localization/cavitation evolved in the center of the forged billet and that this process was not a function of strain rate but rather a function of strain imparted. In the case of discontinuously reinforced aluminum (DRA) composites, preliminary tests on the effects of changes in test temperature, forging rate, and forging strain on the evolution of flow stress, reinforcement distribution, and cracking in the billet are illustrated on sub-scale cylindrical forging specimens with initial dimensions ranging from 1 in. diameter×2 in. height to 2 in. diameter×3 in. height. Forging strains of 0.7 and 1.3 were imparted to the fully dense P/M DRA. In the case of porous P/M DRA, the equipment was used to determine the effects of changes in forging rate on the densification/billet cracking of the porous powder compacts. These results are compared to previous work where a range of forging strains were imparted to determine the effects of changes in forging rate and forging strain on the final density of the powder-forged DRA. The range of conditions that such unique equipment can simulate and the examples provided illustrate the important effects of deformation processing conditions on the resulting structure and properties of such materials in the different regions of the same forging. The relevance of such studies to structure/property evolution in forged components is also emphasized.