Effect of Direct Laser Deposition on Microstructure and Mechanical Properties of 316L Stainless Steel

Direct laser deposition (DLD) is a modern prototyping manufacturing technology, which can directly build full-density and high-performance complex metal parts This paper presents an investigation of the influence different scanning strategy on microstructure and mechanical properties of DLD 316L stainless steel sample. The results showed that formation of fine equiaxed austenitic structure with average grain size of the dendritic cells in 1.2-1.7 μm. Inter-track idle time has directly influence on cooling rate, grain size and mechanical properties. It was shown that the decreasing of inter-track idle time from 4.37 to 0.75 s decreases the ultimate tensile strength from 729 to 686 MPa. For obtaining high mechanical properties of samples or recovering surfaces it is necessary to choose scanning strategy along the largest dimension of the detail.     Keywords: X-ray analysis; Electron microscopy; Stress/Strain measurements; Iron alloys; Laser/Powder methods