Majid Goli - Master student, Isfahan University of Technology, Iran/Mobarakeh Steel Engineering Company
Behzad Niroumand - Professor, Isfahan University of Technology, Iran
Mohammad Raza Toroghinejad - Professor, Isfahan University of Technology, Iran
Mohammad Hossein Mosallanejad - PhD student, Isfahan University of Technology, Iran
Abdollah Saboori - Assistant professor, Polytechnic University of Turin, Italy

Microstructure, defects and hardness of 316L stainless steel fabricated by Direct Metal Deposition (DMD) method were investigated in this study. 316Ll powder was depositedon a substrate of the same composition under the optimum operation parameters in a single-pass mode. Microstructural investigations were conducted along the builddirection as well as transverse to the build direction. Boundaries of the melt pools and the final microstructure were studied by optical microscopy and dimensional measurements were conducted by ImageJ software. Microstructural defects and distribution of the alloying elements were studied using scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS) analysis. Different phases formed in the samples were identified by X-ray diffraction analysis. Hardness measurements were also conducted on the build direction of the sample. Results indicated the formation of a dendritic cellular structure with an average arm diameter of 3.5 micrometers formed at a cooling rate of about 13000 K/s. SEM and EDS analyses revealed formation of a small fraction of delta phase in the microstructure.

Direct metal deposition, 316 stainless steel, microstructure