Nanoscale precipitate in PBF-LB manufactured CoCrMoW alloy and its effect on passive behaviour

• Nanoscale Co 3 (Mo,W) 2 Si precipitates uniformly dispersed on γ-Co matrix of low-carbon PBF-LB CoCrMoW alloy. • Volta potential difference between the Co 3 (Mo,W) 2 Si precipitate and γ-Co matrix was 14 mV. • Nano hardness of Co 3 (Mo,W) 2 Si precipitate was 16.4 GPa, about 1.6 times of that of the matrix. • PBF-LB CoCrMoW alloy exhibited better passive property than wrought high-carbon CoCrMo alloy in 0.9% NaCl solution. A CoCrMoW alloy with little carbon was manufactured through laser beam powder bed fusion technique. Nanoscale intermetallic Co 3 (Mo,W) 2 Si precipitates uniformly dispersed on the γ-Co phase matrix, and caused less segregation of Cr and Mo elements than the microscale carbides in the wrought CoCrMo alloy. Nanoindentation test results showed that the nano hardness of Co 3 (Mo,W) 2 Si precipitate was 16.4 GPa, about 1.6 times of that of the matrix. The Volta potential of nanoscale Co 3 (Mo,W) 2 Si precipitate was 14 mV more positive than the matrix. The corrosion resistance of the PBF-LB alloy in 0.9% NaCl solution was larger than that of the wrought alloy.