A novel Ni40Co18Cr18Fe14Al5Ti5 high entropy alloy with superior mechanical properties and broad printing window via selective laser melting

Abstract

3D printing technology has gained popularity in fabricating high-entropy alloys (HEAs) due to its inherent design adaptability and the capacity to create distinctive structural features. However, the field of 3D-printed HEAs has faced substantial challenges, primarily stemming from a narrow processing window and unsatisfactory mechanical properties. This study unveils a novel Ni40Co18Cr18Fe14Al5Ti5 HEA, suitable for selective laser melting (SLM) technology, showcasing a broad processing window and outstanding mechanical properties. The SLM-produced HEA exhibits near-full density and a hierarchical structure characterized by equiaxed grains without significant texture, cellular structures, and element segregation at cellular boundaries. Remarkably, this HEA demonstrates impressive mechanical performance across various printing parameters, highlighted by a yield strength of 811 MPa, an ultimate strength reaching 1071 MPa, and a tensile elongation of 29 % in the optimized sample. Microstructural analysis reveals that the synergistic effects of dislocation motion, stacking faults, and deformation-induced twinning contribute to the stable strain-hardening capability of the SLM-produced Ni40Co18Cr18Fe14Al5Ti5 HEA.

Keywords

• High-entropy alloy
• Selective laser melting
• Mechanical performance
• Processing versatility
• Deformation twins