A novel microalloying strategy for superior creep performance in LPBF Inconel 718 superalloy

For high-temperature service components, excellent creep performance is critical. However, oxygen embrittlement limits the creep performance of laser powder bed fusion (LPBF) IN718 alloy. This study optimized creep performance by increasing carbon content to 0.45 wt.% and adding 0.06 wt.% yttrium (Y). At 650 °C under 650 MPa and 690 MPa, the 0.06Y-HC alloy exhibited 739% and 671% longer creep life than LPBF IN718 alloy, respectively, approaching the creep performance of wrought IN718 alloy. This improvement stems from Y-induced grain boundary purification, nano-scale Y-rich oxide precipitation. This C/Y microalloying approach effectively optimizes AM superalloys for superior creep performance.