Enhanced wear resistance of AISI 1045 steel by TiAlN/CrN gradient coatings via toughness-hardness synergy

The rotating flange of vehicle chassis AISI 1045 steel is prone to friction-induced failure under high-speed and heavy-load conditions, leading to seal deterioration. This work provides a strategy to enhance the wear resistance by depositing multilayered TiAlN/CrN gradient coating on AISI 1045 steel substrates via arc ion plating. The microstructure, mechanical properties, and tribological behavior of the coating were systematically analyzed. The TiAlN/CrN gradient coating consists of CrN layer, TiAlN/CrN multilayer structure, and TiAlN layer, exhibiting high hardness (38.72 GPa) and elastic modulus (374.83 GPa), along with low residual stress (-448.5 MPa) and average friction coefficient (0.72). The maximum wear scar depth remains below the thickness of the TiAlN surface layer, with abrasive wear identified as the dominant mechanism. The gradient architecture effectively alleviates interfacial stress concentration and reduces residual stress through synergistic effects: ductile buffering by the CrN layer, hardness gradient transition via TiAlN/CrN multilayer, and surface hardening by the TiAlN surface layer. This innovative structural design provides a promising surface engineering solution for enhancing wear resistance of metallic materials under heavy-load operating conditions.