A review of the effect of selective laser melting process parameters and its influence on microstructure, defects and strength in the iron-nickel based superalloy Alloy 718
2016 (English)In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, 1-8 p.Conference paper (Refereed)
This review presents a basic insight into the powder-bed fusion process selective laser melting (SLM), with focus on the microstructure and mechanical properties of the iron-nickel based superalloy Alloy 718. The microstructures and mechanical properties of SLM components are highly affected by the process parameters. Laser power, scanning speed, powder layer thickness and hatch distance, are the primary process parameters which can be adjusted in order to influence the microstructure and minimize potential defects. SLM-manufactured Alloy 718 generally produce a columnar microstructure which is a result of epitaxial formation and dendritic grain growth in the build direction (perpendicular to the substrate). Gas porosity, lack of fusion and residual stresses are process induced problems observed in SLM-manufactured Alloy 718. The microstructure of the as-manufactured Alloy 718 is susceptible to microsegregation of Nb and Mo as well as to subsequent non-equilibrium phase transformation. A post-process heat treatment of as-manufactured Alloy 718 is required in order to improve general mechanical properties and to relieve the residual stresses. The tensile strength, yield strength and hardness of heat treated SLM-manufactured Alloy 718 are comparable to that of wrought material.
Place, publisher, year, edition, pages
Lund: Swedish Production Academy , 2016. 1-8 p.
Selective laser melting, process parameters, Alloy 718, microstructure, defects, strength
Manufacturing, Surface and Joining Technology
Research subject ENGINEERING, Manufacturing and materials engineering
IdentifiersURN: urn:nbn:se:hv:diva-10142OAI: oai:DiVA.org:hv-10142DiVA: diva2:1052804
7th International Swedish Production Symposium, SPS16, Lund, Sweden, October 25–27, 2016