Dependence of Microstructure, Relative Density and Hardness of 18Ni-300 Maraging Steel Fabricated by Selective Laser Melting on the Energy Density
18Ni-300 maraging steel samples were fabricated by Selective Laser Melting technology (SLM). Microstructure and phase transformation before and after aging treatment were investigated by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Meanwhile, hardness and relative density of samples were also tested. The results showed that there was a positive correlation relationship between energy density and relative density. Samples fabricated with high energy density of 6.0 J/mm2 could lead to extremely high relative density of 99.34%; After aging heat treatment (763 K for 4 h), the microhardness increased from 370 to 629 HV because of second phases such as Ni3Mo and Ni3Ti precipitated in the martensite matrix. When aging temperature reached to 793 K, the hardness was affected by both precipitation of strengthening phase and austenite reversion which had the opposite effect. The XRD results showed the appearance of austenite and the decrease of martensite.
KeywordsSelective laser melting 18Ni-300 maraging steel Microstructure Mechanical properties
This work is supported by the Guangdong Key Laboratory of Metal Toughening Technology and Application (2014B030301012), Guangzhou Key Laboratory of Advanced Metal Structural Materials (201509010003), Major Science and Technology Projects in Guangdong Province(2014B01013100 and 2016B090914001), Special Environment and Ability Construction on Scientific Research Platform of Guangdong Academy of Science (2016GDASPT-0320), Project on the Integration of Industry, Education and Research of Guangdong Province (2014B090903016).
- 3.X.L. Li, J.X. Ma, P. Li, Q. Chen, W.M. Zhou, 3D printing technology and its application trend. Process Autom. Instrum. 35(1), 1–5 (2014)Google Scholar
- 5.R. Casati, J. Lemke, M. Vedani, Microstructure and fracture behavior of 316L austenitic stainless steel produced by selective laser melting. J. Mater. Process. Technol. 32, 738–744 (2016)Google Scholar