Autor(es): Martins, Ricardo ; Gonçalves, António Pereira ; Correia, J.B. ; Galatanu, Andrei ; Alves, E. ; Tejado, Elena ; Pastor, Jose Ygnacio ; Dias, Marta
Data: 2024
Identificador Persistente: http://hdl.handle.net/10400.9/4304
Origem: Repositório do LNEG
Assunto(s): High entropy alloys; Monte Carlo simulation; Molecular mechanics; Thermal properties; Mechanical properties
ABSTRACT: Developing new materials to be applied in extreme environments is an opportunity and a challenge for the future. High entropy alloys are new materials that seem promising approaches to work in nuclear fusion reactors. In this work, FeTaTiVW high entropy alloys were developed and characterized with Molecular Dynamic and Hybrid Molecular Dynamic Monte Carlo simulations. The simulation results show that phase separation originates a lower potential energy per atom and a high level of segregation compared to those of a uniform solid solution. Moreover, the experimental diffractogram of the milled powder shows the formation of a body-centred cubic-type structure and the presence of TiO2. In addition, the microstructure of the consolidated material evidenced three phases: W-rich, Ti-rich, and a phase with all the elements. This phase separation observed in the microstructure agrees with the Hybrid Molecular Dynamic Monte Carlo simulation. Moreover, the consolidated material's thermal conductivity and specific heat are almost constant from 25 degrees C to 1000 degrees C, and linear expansion increases with increasing temperature. On the other hand, specific heat and thermal expansion values are in between CuCrZr and W values (materials chosen for the reactor walls). The FeTaTiVW high entropy alloy evidences a ductile behaviour at 1000 degrees C. Therefore, the promising thermal properties of this system can be attributed to the multiple phases and systems with different compositions of the same elements, which is exciting for future developments.
