Work

Inconel 625/Al2O3 functionally graded materials manufactured by directed energy deposition

Year: 2026

Type: article

Abstract: Partial repairing using additive manufacturing becomes one of the important issues to provide maintenance, repair, and overhaul service for gas turbine components. Owing to small heat-affected zones, recent additive manufacturing methods enable us to deposit non-weldable Ni-based superalloys on damaged components. Although additive manufacturing can be a strong candidate for the partial repair of Ni-based superalloy components, the repair of thermal barrier coating remains a critical issue in partial repairing. In this study, the feasibility of using directed energy deposition for fabricating an Inconel 625/Al 2 O 3 functionally graded material is investigated. By combining surface forces and convection during deposition, intermixing between Inconel 625 and Al 2 O 3 occurs, resulting in bonding within a functionally graded structure. Both thermal conductivity and flame thermal-gradient test results revealed that the deposited Al 2 O 3 reduces the temperature of IN625 substrate even at 1300 °C environment. Although the omission of bond-coat layer causes a low adhesion strength (8.33 MPa) at the interface between IN625 and Al 2 O 3 deposit layers, the present result represents that directed energy deposition could be an alternative method to achieve thermal barrier coatings on hot components.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2026.01.064