Selective Laser Melting of Superalloys: The Influence of laser Scanning Parameters and Strategies on Microcracking and Microstructure.

Microcracking is currently one of the main obstacles of implementing Selective Laser Melting (SLM) in many conventional superalloys. Available research so far hints that the cracking is mainly related to high temperature phenomena such as solidification. One of the main factors in the SLM solidification process is the laser scanning inputs and the resultant metallurgical reaction of the alloys. In this research, we are reporting our funding on how different laser scanning parameters (e.g. laser power, scan speeds etc.) and scanning strategies (e.g. alternating, 67 rotation etc.) can have large influence on the microcracking and microstructure. Several γ'-bearing Ni-based superalloys were test printed with different laser scanning settings and different types of samples. Various types of microscopies as well as modelling techniques were utilized to explain the differences in cracking and microstructure. The results indicate that proper selection of scanning strategies can mitigate the crack susceptibility with some drawbacks, while the selection of laser parameters requires a very careful balance between productivity (in terms of laser scanning efficiency) and crack suppression. This presentation aims to provide a better understanding in some of the effective means of reducing the microcracking in the SLM process, contributing to the adaptation of more additive manufactured high-performance superalloys in the aerospace industry.