Process optimization and mechanical properties of oxide dispersion strengthened nickel-based superalloy by selective laser melting

Abstract

Oxide dispersion strengthened nickel-based superalloy (ODSN) is widely used in structural materials such as aerospace and nuclear industry, but its uniform dispersion distribution of particles makes it only necessary to manufacture using conventional powder metallurgy technique. Selective laser melting (SLM) is first selected as a novel method for manufacturing ODSN. The influence of SLM process parameters (laser power, scanning speed, hatch spacing) on the microstructure and mechanical property in ODSN has been investigated, using Taguchi method (TM) and Response surface methodology (RSM). Orthogonal array and Box-Behnken design were utilized to design the experiments. Analysis of variance, signal-to-noise ratio, main influence diagrams, 3D response surface, and the corresponding contour plots were measured to evaluate the effects of factors on the tensile strength. By comparing the results of the experiment showed that optimum parametric combination from TM and RSM induced better tensile strength. The optimum process parameters were predicted, validated, and subsequently employed to build samples to assess mechanical properties during 25–1000 °C. The samples produced using SLM showed approximate tensile strength, compared to hot extruded ODSN of similar composition. Fracture morphology results good agreement with mechanical property at room and elevated temperature.