Ni-Al-Mo based alloys can be used as materials for high temperature applications. They can be prepared by various techniques such as an electron beam zone melting, which allows us to obtain the alloys with a directionally solidified structure and unique properties. A plasma-melted Ni-Mo master alloy was used for the preparation of the experimental alloys. Ni-Al-Mo alloys were melted in an induction furnace and then cast centrifugally in the form of bars. These bars were then re-melted in the electron beam zone furnace. The structure of these alloys was multi-phase. The structure was formed by the phases Ni₃(Al,Mo) and (Ni) with variable content of molybdenum. The structure also contained particles rich in molybdenum (Mo, MoNi). The alloys were submitted to the compression tests at a temperature of 800 °C. The yield strength of alloys achieved the value of approx. 800 MPa. The different molybdenum content affected the values of the maximal flow stress. The alloys with higher molybdenum content showed higher maximal flow stress, namely approx. 1300 MPa. The results show that these alloys are very promising for the production of structural components operating at elevated temperatures.

Flywheel energy storage systems impose high demands on the mechanical properties and structural integrity of rotors, particularly in high-speed applications. This study focuses on the numerical analysis of gravity casting of a steel rotor manufactured from low alloy 34CrMo4 steel, with the aim of identifying critical regions related to molten metal flow, solidification behaviour and shrinkage defect formation. Numerical simulations were calculated using a MAGMASOFT^® 5.5 software environment based on the finite volume method and included both mold filling and subsequent solidification and cooling stages. Flow stability, temperature field distribution and solidification characteristics were researched thoroughly. The results showed that optimization of the gating and feeding system lowered porosity under 2% within the casting and relocated shrinkage defects to the risers. At the same time, solidification directionality was improved and the Hot Spot value was reduced. From the perspective of casting quality, the proposed design represents the most suitable solution, despite a lower metal utilization rate. The analysed casting forms the structural body of a hybrid flywheel rotor intended for the subsequent integration of high-density tungsten segments.