پديدآورندگان :
Saeidi K. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden; , Gao X. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden , Lofaj F. Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, 916 24 Trnava, Slovak Republic , Kevetkova L. Institute of Materials Research of the Slovak Academy of Sciences, Watsonova 47, Košice, Slovakia , Shen Z. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
كليدواژه :
Stainless steel , Selective laser melting , intra , granular cellular sub , grains , mechanical properties
چكيده فارسي :
Austenitic 316L stainless steel is widely used for its good formability and excellent toughness however; it lacks the required hardness and strength. Selective laser melting (SLM) is a layer wise bottom up technology in which can develop 316L steel bodies with enhanced mechanical properties; therefore SLM can successfully tailor and manipulate the microstructure. Careful SEM/TEM microstructural studies revealed an intra-granular cellular sub-grain structure of size 0.5-1 μm which was confined in larger single-crystal grains in the range of 10-100 μm. Molybdenum was found to be enriched at the sub-grain boundaries. Nevertheless, high concentration of dislocations was also formed around the sub-grain boundaries throughout the entire microstructure forming a network. In-situ oxide nano inclusions with size around 50 nm were evenly distributed in the steel matrix. The micro hardness, tensile and yield strength of the SLM samples were measured 325 HV, 703± 8 Mpa and 456± 17 MPa respectively which are much greater compared to HIP 316L steels with microhardness, and yield strength of 170HV and 220 MPa respectively. The fine cellular grains along with multi-scale interlocking and texture resulted in high toughness of the SLM 316L despite its high strength.
