Impact of post-heat treatment on the mechanical and tribological properties of GH4169/V coatings produced by laser cladding

GH4169 coatings produced by laser cladding are commonly used in high-temperature applications. However, during the rapid solidification process, deleterious Laves phases form in these coatings, which significantly diminish their mechanical properties and indirectly affect their wear resistance. To address this, GH4169 superalloy with 3 % Vanadium content was developed to alter the segregation of Nb elements and reduce the formation of harmful Laves phases. The study aimed to evaluate how heat treatment affects the mechanical and tribological properties of GH4169/V coatings. After applying a low-temperature solid solution followed by double aging heat treatment, δ-phases formed separately while γ′and γ’’ phases appeared in the γ matrix of the coatings. This treatment led to a significant increase in average microhardness, i.e., about 69 %. Additionally, tensile strength increased from 804 MPa to 1070 MPa (+40 %), while elongation at fracture decreased from 20.6 % to 14.4 % (−30 %). The tensile fracture mechanism shifted from ductile to a combination of plastic and brittle fracture. The maximum shear force at fracture improved from 35.60 kN to 53.4 kN, and shear strength increased by 50 %. Post-standard heat treatment, the coating exhibited a reduced coefficient of friction across various temperatures (200 °C, 400 °C, 600 °C). At lower temperatures (25 °C, 200 °C), the wear rate increased, whereas, at higher temperatures (400 °C, 600 °C), it decreased. The superior tribological properties of the GH4169/V coating, both before and after heat treatment at 400 °C and 600 °C, are attributed to the formation of a continuous oxide film. Moreover, the precipitated reinforcing phases from heat treatment enhanced the coating's hardness, further improving its wear resistance at high temperatures.