Design and fabrication of lightweight AlCrFeNiTix compositionally complex alloys with exceptional specific strength

This study focuses on compositionally complex alloys (CCAs), aiming to achieve a balance between high strength and low density for new energy and aerospace applications. The composition of AlCrFeNiTix CCAs is strategically guided by employing density functional theory and the theoretical design of thermodynamic calculations. Bulk CCAs, particularly AlCrFeNiTi0.25 alloy, demonstrate remarkable specific yield strength (1640.8 MPa) and 22.7% maximum strain. The incorporation of Ti facilitates the formation of lightweight and high-strength L21 phase, contributing to the overall high specific strength. Synergistic effects of grain boundary strengthening, solid solution strengthening, Orowan strengthening and Peierls flow stress further enhance strength. Detailed exploration of microstructural changes during fracture reveals the role of ordered phases in suppressing crack propagation and absorbing energy within disordered phases, thereby improving the toughness and fracture resistance of CCAs. These methods and discoveries establish a robust foundation for advancing the development of novel lightweight CCAs.