Formability and hardness studies of selective laser melting of GH4169 Ni-based alloy powders

Selective laser melting (SLM) is a new three-dimensional printing technology capable of directly manufacturing metal end products and near-end products. Currently, the processing of nickel (Ni)-based alloy powders by SLM technology has not been reported yet. Considering this, this paper lays the foundation for developing relevant SLM technology by experimenting with GH4169 nickel-based alloy powders using an LWY400P laser. The paper deals primarily with single-layer, single-path and single-layer, multipath scan processes in order to explore the mechanisms of the effects of laser process parameters (e.g. current, frequency, pulse width, scan speed and scan spacing) on the formability of GH4169 nickel-based alloy powders. Process optimization was carried out as well. The optimized SLM process involved a parameter group comprising a 140 A laser current, a 150 mm/min scan speed, a 0.35 mm scan spacing, a 5.5 ms pulse width, a 12 Hz frequency and a 0.15 mm coating thickness. Under the optimized parameter group, a 427 HV microhardness was observed. Meanwhile, the formed products had a basically flat surface, a uniform microstructure and a high density.