Low activation Ti30V30Cr5Zr5Ta30-XWX refractory high entropy alloys with excellent mechanical properties and phase stability
Shunhua Chen, Yaocai Tang, Junsheng Zhang, Xiaokang Yue, Haidong Yang, Huohong Tang, Yucheng Wu
Abstract
Although refractory high entropy alloys (RHEAs) have the potential to serve as nuclear materials, designing a high-performance alloy that can simultaneously endure extreme environments, such as elevated temperatures and radiation exposure, remains a significant challenge. In this work, elements with high melting points and low activation characteristics are selected to design Ti 30 V 30 Cr 5 Zr 5 Ta 30-x W x (x = 5, 10, 15, 20 at.%) RHEAs that exhibit good high-temperature strength and irradiation resistance. The phase structure, mechanical properties, deformation mechanisms , and irradiation resistance of the RHEAs were investigated and discussed. All the low-activation Ti 30 V 30 Cr 5 Zr 5 Ta 30-x W x RHEAs exhibited excellent phase stability. Typically, the Ti 30 V 30 Cr 5 Zr 5 Ta 15 W 15 RHEA exhibited a yield strength, specific yield strength, and plasticity of 1607 MPa, 172.42 MPa·cm 3 /g and 22.7 % respectively at room temperature. At 800 °C and 1000 °C, it still had a yield strength of 851 MPa and 558 MPa respectively. The high strength of the Ti 30 V 30 Cr 5 Zr 5 Ta 15 W 15 RHEA was attributed to the solid solution strengthening mechanism, in which the W element played an important role. The deformation mechanism of Ti 30 V 30 Cr 5 Zr 5 Ta 15 W 15 RHEA at both room temperature and elevated temperatures was primarily governed by dislocation slip. Using low-energy and high-flux He ions , the irradiation resistance of the Ti 30 V 30 Cr 5 Zr 5 Ta 20 W 10 and Ti 30 V 30 Cr 5 Zr 5 Ta 15 W 15 RHEAs were also investigated. They demonstrated better radiation resistance surpassed that of pure W, showing remained flat surface and stable phase structure.