Microstructural Evolutions and Mechanical Properties of Energetic Al 1 (TiZrNbTaMoCr) 15 High-Entropy Alloys

The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al 1 (TiZrNbTaMoCr) 15 refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B2 microstructure with needle-like B2 nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al 1 Ti 6 Zr 2 Nb 3 Ta 3 Mo 0.5 Cr 0.5 alloy. Therefore, this alloy exhibits the highest compression yield strength ( σ YS = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B2 microstructure underwent destabilization, and the B2 phase transforms into the brittle Zr 5 Al 3 phase which then coarsens and dominates the microstructure of S3-AlTa 3 alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (Δ H ), surpassing 11606 J·g −1 , which highlights their significant potential as innovative high-performance energetic structural materials.