High entropy alloys (HEAs) are promising materials for applications in structural elements of future fusion and fission reactors [1] due to their superior radiation resistance properties compared to pure elements and conventional alloys. In this work, we focus on the bcc Ta-Ti-V-W alloys, which have been shown from our ab initio-based Monte Carlo simulations to have the lowest solid solution temperature among five-component (Cr-Ta-Ti-V-W) HEAs [2].

The samples of high-entropy alloys from the Ta-Ti-V-W system were synthesized using arc-melting. In order to investigate the microstructure evolution of HEAs as a function of heat treatment conditions, the samples were annealed at different temperatures. Both the as-received and annealed samples were characterized using X-ray diffraction (XRD), visible light microscope, and scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS).

The preselected equiatomic composition from the Ta-Ti-V-W system [1] was laser-remelted using LPBF device to preliminary characterize phase evolution during AM-process. The powder was atomized using the rePowder device manufactured by AMAZEMET. The device was equipped with a 40kHz ultrasonic system for atomization and a 350A DC plasma source for melting the material [3]. Powders were characterized by scanning electron microscope (SEM). The particle size distribution was measured using laser diffraction Single track experiments were investigated to verify in situ cracking behaviour and alloy supersaturation as a function of basic laser parameters (beam speed and power). The later remelted layer was used to investigate line-to-line interference and interlayer stress via X-ray diffraction (XRD).

References

[1] O. El-Atwani, N. Li, et al., Sci. Adv. 5 (2019) eaav2002.

[2] D. Sobieraj, J.S. Wróbel, et al., Phys. Chem. Chem. Phys. 22 (2020) 23929.

[3] Ł. Żrodowski, R. Wróblewski, et al., Materials 14 (2021) 2541.