Untersuchungen zum Rekristallisationsverhalten von Molybdän

Molybdenum is a refractory metal and is mainly produced by powder metallurgy. During the production process, the material is deformed and exposed to several heat treatments. Depending on the mode of deformation and the subsequent heat treatment the material may form a new microstructure via recrystallization. By using a recrystallization diagram it is possible to predict the recrystallized grain size. Due to rising standards in the production of molybdenum, the amount of impurities decreased considerably over time and therefore existing recrystallization diagrams forfeit their accuracy. As a consequence the aim of this diploma thesis was to establish a new recrystallization diagram and to investigate the recrystallization kinetics by implementing state-of-the-art characterization techniques such as EBSD and ECCI. By using these techniques it was possible to distinguish between recrystallized and still deformed grains and therefore the recrystallization behavior of molybdenum could be investigated on a high level of accuracy. Investigations on the light microscope and SEM were approved by additional hardness measurements.