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2016
Conference Paper
Titel
Reactions and microstructure evolution during sintering of high purity aluminium in nitrogen
Abstract
High purity aluminium powder was sintered in a dilatometer in flowing high purity nitrogen. Distinct shrinkage segments observed on the dilatometry curves were the basis of interrupted sintering experiments. Microstructures "frozen" at different steps of the sintering cycle were thus produced. Optical microstructural examination and LECO analysis of nitrogen content showed the development of aluminium nitriding. Additionally X-ray diffraction was used to examine the appearing phases. Evidence is presented that isothermal sintering proceeds in the presence of a liquid phase, despite taking place below the melting point of aluminium. It seems that aluminium-nitrogen exothermal interactions are responsible for the appearance of the liquid phase, accompanied by extensive shrinkage.