Microstructural Transformation and Corrosion Property Improvement of CoCrFeNiTi‐Based Multi‐Principal Element Alloys Fabricated via Laser Powder Bed Fusion

Herein, CoCrFeNiTi‐based multiprincipal element alloys (MPEAs) are proposed to meet the demands of high mechanical strength and corrosion resistance in additively manufactured products. Two types of MPEAs with different chemical compositions are obtained by laser powder bed fusion (LPBF) using gas‐atomized prealloyed powders. Both MPEAs as‐built products have columnar crystal structures with face‐centered cubic (FCC) phase matrices. In the solution and aging heat treatment, columnar crystal grains transform into equiaxial recrystallized grains with precipitates dispersed in the FCC matrix. The alloys exhibit ultimate tensile strength over 1500 MPa and corrosion rates of less than 1 mm year⁻¹ in boiling 10% H₂SO₄. The microcellular structures formed in the LPBF process, and the precipitates formed after heat treatments can affect the mechanical properties and corrosion behavior. The higher cobalt and chromium content of the proposed CoCrFeNiTi‐based MPEA and the microstructure control in heat treatments demonstrate their effectiveness in retarding acid corrosion.