Influence of Hf on the heat treatment response of additively manufactured Ni-base superalloy CM247LC

The influence of Hf on the heat treatment response a Laser Powder Bed Fusion (L-PBF) fabricated Ni-base superalloy was investigated. A Hf-free version CM247LC, CM247LC NHf, and (~1.4 wt% Hf) were subjected to identical thermal treatments characterized. After solutionizing at 1260 °C for 2 h, both alloys displayed recrystallization grain growth. NHf had numerous annealing twins suggesting that inhibits twin formation. alloy lower peak hardness than (5000 MPa 5200 MPa, respectively) this attributed ~6% point reduction (Calphad calculated) in ?? phase fraction due removal Hf. Despite values, higher yield strength 760 (969 926 respectively). Elongation fracture similar (~1%) NHf. shown be effective mitigating strain age cracking susceptibility likely decrease ?’ lattice mismatch.