High pressure and high temperature behavior of TiAlN

Sammanfattning: This licentiate thesis mainly reports about the behavior of arc evaporated TiAlN at high pressures and high temperatures. The extreme conditions have been obtained in metal cutting, multi anvil presses or diamond anvil cells. Several characterization techniques have been used, including x-ray diffraction and transmission electron microscopy.Results obtained during metal cutting show that the coatings are subjected to a peak normal stress in the GPa region and temperatures around 900 °C. The samples after metal cutting are shown to have a stronger tendency towards the favorable spinodal decomposition compared to heat treatments at comparable temperatures. We have also shown an increased anisotropy of the spinodally decomposed domains which scales with Al composition and results in different microstructure evolutions. Furthermore, multi anvil press and diamond anvil cell at even higher pressures and temperatures (up to 23 GPa and 2200 °C) also show that the unwanted transformation of cubic AlN into hexagonal AlN is suppressed with an increased pressure and/or temperature.