Strong yet ductile (FeCoNi)86Al7Ti7 high-entropy alloy via laser powder bed fusion

Abstract

High entropy alloys (HEAs) are renowned for their outstanding mechanical properties and thermal stability, yet their complex compositions pose significant processing challenges. This study introduces an innovative approach using Laser Powder Bed Fusion (LPBF) to directly fabricate the (FeCoNi)AlTi HEA, bypassing the extensive post-processing typically required. Unlike Vacuum Arc Melting (VAM), the LPBF method produces a refined microstructure with fine cellular substructures, elemental segregation, and L2 phase nano-precipitates. These features contribute to significantly improved mechanical performance, with the LPBF-produced alloy achieving an ultimate tensile strength of 1221.6 MPa and a tensile strain of 32.6 %, compared to the VAM-produced HEA, which exhibits an ultimate tensile strength of 972.5 MPa and a tensile strain of 8.8 %. This work demonstrates that LPBF can not only achieve but enhance the properties of HEAs, offering a streamlined and effective alternative to conventional methods. The findings underscore the transformative potential of LPBF in shaping high-performance HEAs, eliminating the need for additional treatments, and opening new avenues for advanced material design.