Unveiling the Role of the Residual Stress in TiC‐Based Self‐Healing Coating on the Creep‐Fatigue Properties of 321 Steel

ABSTRACT Residual stress in coatings significantly influences stainless steel mechanical properties, particularly tensile and creep‐fatigue performance. This study combines experimental characterization and multiscale finite element analysis (FEA) to systematically investigate these effects on coated AISI 321 steel. A TiC‐based self‐healing coating system—comprising Al 2 O 3 ‐13wt%TiO 2 (AT13), TiC, and NiCrAlY layers—was deposited via supersonic plasma spraying. Macroscale FEA and microindentation testing characterized the residual stress distribution, showing strong agreement between simulation and experiment. Integrated multiscale modeling revealed that spray parameters (pass frequency and deposition thickness) critically govern residual stress development. The resulting compressive stresses enhanced tensile properties through stress compensation and improved creep‐fatigue resistance via load redistribution. Under cyclic loading (180 MPa, 5‐s dwell), the coated specimens exhibited an 18.4% increase in yield strength and a 26.3% extension in creep‐fatigue life compared to uncoated samples.