TY - JOUR
T1 - The Effect of Microstructure and Surface Finish on the High Temperature Oxidation of Laser Powder Bed Fused IN625
AU - Lewis, E. R.
AU - Cruchley, A. C.
AU - Attard, B.
AU - Gao, Z.
AU - Cruchley, N.
AU - Attallah, M. M.
AU - Cruchley, S.
PY - 2026/2
Y1 - 2026/2
N2 - Isothermal oxidation of Laser Powder Bed-Fused (L-PBF) IN625 was investigated in air at 950 ℃ for 1000 h, across multiple heat-treated and surface conditions. Surface finish was the dominant factor influencing oxidation kinetics, with microstructure exerting a measurable secondary effect. Ground L-PBF IN625 exhibited oxidation behaviour comparable to wrought Ni-based superalloys, regardless of microstructural anisotropy. Additive surface roughness and Centrifugal High Energy Finished surfaces exhibited accelerated kinetics and a departure from sub-parabolic to cubic behaviour, showing spallation, severe void formation and intergranular oxidation. Segmented kinetic analysis revealed that additive surfaces exhibited an oxidation rate index (n > 2) during early exposure, followed by a transition to slower growth. Mn-spinel was detected throughout the external scale, but its mechanistic contribution to this transition remains uncertain. Growth of the near-continuous Ni3(Nb, Mo) δ-phase varied by condition and is proposed to improve the adherence of chromia by increasing the critical temperature change for spallation.
AB - Isothermal oxidation of Laser Powder Bed-Fused (L-PBF) IN625 was investigated in air at 950 ℃ for 1000 h, across multiple heat-treated and surface conditions. Surface finish was the dominant factor influencing oxidation kinetics, with microstructure exerting a measurable secondary effect. Ground L-PBF IN625 exhibited oxidation behaviour comparable to wrought Ni-based superalloys, regardless of microstructural anisotropy. Additive surface roughness and Centrifugal High Energy Finished surfaces exhibited accelerated kinetics and a departure from sub-parabolic to cubic behaviour, showing spallation, severe void formation and intergranular oxidation. Segmented kinetic analysis revealed that additive surfaces exhibited an oxidation rate index (n > 2) during early exposure, followed by a transition to slower growth. Mn-spinel was detected throughout the external scale, but its mechanistic contribution to this transition remains uncertain. Growth of the near-continuous Ni3(Nb, Mo) δ-phase varied by condition and is proposed to improve the adherence of chromia by increasing the critical temperature change for spallation.
UR - https://link.springer.com/journal/11085
U2 - 10.1007/s11085-025-10369-9
DO - 10.1007/s11085-025-10369-9
M3 - Article
SN - 2731-8397
VL - 103
JO - High Temperature Corrosion of Materials
JF - High Temperature Corrosion of Materials
IS - 1
M1 - 12
ER -