OBJECTIVES AND LAYOUT OF THE THESIS;
Objectives
In the design of a metal forming process, the only factors that are known are the final product shape and the material with which it is to be made. The fundamental goal of process design in extrusion is to produce industrial parts with high quality, precise dimensions in a most economical way. In this endeavor process optimization is of immense importance. In this thesis Equal Channel Angular Pressing (ECAP) is modeled using finite element method and the evolution of strain in the specimen, extrusion force and forming energy needed during severe
plastic deformation for various input parameters are computed. The purpose of this work is to formulate an integrated modeling approach where optimal…show more content… It makes up about 9% of the earth's crust, making it the most abundant of all metals. The potential military applications of this metal led to a strategic importance and consecutively developed a wide range of industrial usage areas. The largest single use of aluminum alloys is in the transportation industry. Car and truck manufacturers use SPD processed aluminum alloys because they are strong, but lightweight. Another important use of aluminum alloys is in the packaging industry. Aluminum foil, drink cans, paint tubes, and containers for home products are all made of aluminum alloys. Other uses of aluminum alloys include window and door frames, screens, roofing, siding, electrical wires and appliances, automobile engines, heating and cooling systems, kitchen utensils, garden furniture, and heavy machinery. Aluminum is also made into a large variety of compounds with many industrial and practical uses. Aluminum ammonium sulfate is used as a mordant, in water purification and sewage treatment systems, in paper production and the tanning of leather, and as a food…show more content… This formation of new HAGB’s is based on three mechanisms [SEV80]. The first step or mechanism involves the elongation of existing grains which leads to increase in high angle boundary area during deformation of material. In the second mechanism, grain subdivision takes place leading to the formation of high angle boundaries and in final step due to formation of shear bands. this elongated grains split up into smaller grains. This happens based on the fact that when original grain is plastically deformed, formation of new boundaries inside the grain takes place [Lan69. Sev80. Han97]. During deformation with low strain rates, grain breaks up in cell and cell blocks [Bay92] which leads to gain subdivision and with increase in deformation this substructure changes into a lamellar structure with the formation of new high angle grain boundaries. The main reason behind the formation of this new HAGB's is by the combined action of texture and microstructural mechanisms [Han97]. The changes in microstructure begin at low deformations which lead to the accumulation of dislocations along cell boundaries where as the strain increases misorientations also increase. Still at this situation some boundaries remains as LAGB while significant number of grains have evolved as medium-high angle grain boundaries in the range of 150-300. At the same time when these