Abstrakt
In this work, the evolution of microstructure and mechanical properties of FeAlCrV and FeAlCrMo medium entropy alloys were studied. In both FeAlCrV and FeAlCrMo alloys, the as-cast sample is a body centered cubic (BCC)-ordered solid solution.
In FeAlCrMo, it exhibits a dendritic structure, whereas in FeAICrV, two types of particles are present. The first one is the solid solution VxCr1-x (0.8 < x < 1) with the BCC structure and the second one is the V2C carbide with orthogonal symmetry.
In FeAICrV, the structure of the investigated material remains stable even after annealing at 800 degrees C for 15 days. Nevertheless, vanadium starts to redistribute, and the lattice parameter slightly changes at a temperature of 500 degrees C.
Furthermore, a new solid solution enriched in vanadium forms. In FeAlCrMo, a lengthy annealing at a high temperature (800 degrees C/15 days) results in decomposition into a two-phase material composed of a BCC solid solution and a Mo3Al phase with a primitive cubic (PC) structure.
Differential scanning calorimetry and dilatometry revealed that decomposition already starts at the temperature of approximately 400 degrees C. Compression deformation tests were performed at various temperatures starting from room temperature (RT) up to 800 degrees C.
The results showed that both materials exhibit excellent values of yield stress, especially at high temperatures (965 MPa and 898 MPa at 800 degrees C for FeAICrV and FeAlCrMo, respectively). The plasticity reaches 5-12% and 3-9%, respectively.