Laser Direct Metal Deposition (LDMD) has developed for a range of diverse applications, from high precision manufacturing to repair. Although functional grading of surface coatings is well established, research into three-dimensional intermetallic grading as an alternative to welding is ongoing. This paper considers the functional grading of Ti-6Al-4V to Inconel 718 for aerospace applications.
A 1.5 kW diode laser and LDMD system is used to produce a series of graded thin wall deposits. Images of the process are captured using Cu-vapour illumination and a high speed camera with long range microscopy optics and quantitative results extracted via image analysis. Process parameters, in process variables such as quantified melt pool disturbance, and final part characteristics are then correlated and discussed. By monitoring in process variables, the work aids in better understanding what happens during LDMD, especially when material transition occurs, and how this leads to final deposit characteristics.