Tailoring L21 strengthening in lightweight AlFeNiTiV complex concentrated alloys for elevated-temperature applications

Abstract

Complex concentrated alloys (CCAs) containing the L2₁ phase are recognized for their exceptional strength and thermal stability, positioning them as strong candidates for transformative applications in aerospace, energy, and structural sectors. This investigation delves into the AlFe_xNiTiV_40−x (x = 0, 10, 20, 30, 35, 40; at%) CCAs, aiming to unlock the synergistic potential of BCC and L2₁ phases. By conducting an in-depth analysis of microstructure, phase behavior, and mechanical properties, the intricate relationships between chemistry, structure, and properties are illuminated within this alloy system. The Al₁₅Fe₃₅Ni₃₀Ti₁₅V₅ alloy demonstrates remarkable mechanical properties, achieving a yield strength of 2140.9 MPa and ultimate compressive strength of 2699.7 MPa, primarily through solid solution strengthening and precipitation hardening. Notably, its low lattice mismatches and nanoprecipitate strengthening yield an impressive specific yield strength at 600 °C (245.2 MPa(g·cm⁻³)⁻¹). Phase modulation achieves the synergistic optimization of specific strengths at both room and high temperatures in CCAs containing the L2₁ phase, opening new avenues for designing advanced lightweight and high strength alloys for elevated-temperature applications.

Graphical abstract