Increasing CO2 and NOx emissions and the associated global warming require a consequent reduction in fuel consumption in the automotive industry. In order to achieve this goal, the development of more efficient combustion engines will be necessary, due to immature alternative technologies. Thereby, especially down-sizing combined with the use of exhaust turbochargers plays a central role, which utilizes a part of the heated exhaust gases to actuate a supercharger and, thus, to make a contribution to enhance the performance. It is necessary to improve the response behavior by reducing the inertia of the turbocharger to achieve a further increase in driving comfort and efficiency. Consequently, the need for the development of improved light-weight high temperature materials increases. Due to their low density, their high specific strength and stiffness at elevated temperatures as well as their good oxidation and creep resistance titanium aluminide alloys represent an excellent option as high temperature and light-weight materials. The γ-TiAl based alloys, investigated in this work, were produced through a powder metallurgical process by means of metal injection moulding (MIM) or, comparatively, by hot isostatic pressing. One of the advantages of the MIM process is the possibility to manufacture high quantities of complex components at near net shape. The aim of this study was to determine the influence of oxygen, which is introduced by the MIM process, as well as the effect of zirconium on microstructure, solidification path, phase transformation temperatures and, consequently, on the mechanical properties of the investigated alloys. At first, a basic characterization of the differently compacted samples was performed using optical and scanning electron microscopy, X-ray diffraction and hardness measurements. Secondly, the influence of oxygen and zirconium on the phase diagram was verified via differential scanning calorimetry and additional heat treatment studies which were compared to thermodynamic calculations.