Laser Remelting Process Simulation and Optimization for Additive Manufacturing of Nickel-Based Super Alloys

Abstract

Nickel-based super alloys are popular for applications in the energy and aerospace industries due to their excellent corrosion and high-temperature resistance. Direct metal deposition (DMD) of nickel alloys has reached technology readiness for several applications, especially for the repair of turbomachinery components. However, issues related to part quality and defect formation during the DMD process still persist. Laser remelting can effectively prevent and repair defects during metal additive manufacturing (AM); however, very few studies have focused on numerical modeling and experimental process parameter optimization in this context. Therefore, the aim of this study is to investigate the effect of determining the remelting process parameters via numerical simulation and experimental analyses in order to optimize an industrial process chain for part repair by DMD. A heat conduction model analyzed 360 different process conditions, and the predicted melt geometry was compared with observations from a fluid flow model and experimental single tracks for selected reference conditions. Subsequently, the remelting process was applied to a demonstrator repair case. The results show that the models can well predict the melt pool shape and that the optimized remelting process increases the bonding quality between base and DMD materials. Therefore, DMD part fabrication and repair processes can benefit from the remelting step developed here.

Hybrid Laser Additive Manufacturing of Metals: A Review

“…Laser remelting melts coarse columnar grains, inhibits grain growth, and results in a more uniform composition distribution, optimizing the alloy's microstructure, reducing surface roughness, and improving mechanical properties such as wear and corrosion resistance [49][50][51]. In general, there are two types of laser remelting treatments, surface remelting and interlayer remelting, with surface remelting applied only to the last layer of the part.…”

Reducing Oxidation during Direct Metal Deposition Process: Effects on Ti6Al4V Microstructure and Mechanical Properties

“…The temperature fields were simulated numerically with the Comsol Multiphysics 6.1 software. Two different models were developed for the calculation of these, differing only in that, in one model, the melt pool flow was considered and, in the other, it was not, in order to achieve a higher computational efficiency, as mentioned in Soffel et al [26]. Detailed information on the simulation approach is described in Wirth and Wegener [27] and can be taken from there.…”

Novel Assessment Methodology for Laser Metal Deposition of New Metallic Alloys

“…Simulation tools can also be used to simplify the procedure for process parameters’ determination in AM. Soffel et al [ 24 ] performed the optimization of remelting process parameters for part repair in DED via numerical simulation. The models predicted the melt pool shape, and they concluded that the optimized remelting parameters increased the bonding quality between the base and deposited materials.…”