Multiscale finite element modeling to achieve the mechanical properties of FSPed and SiC-reinforced austenitic 316L stainless steel produced by selective laser melting

In this study, austenitic 316L stainless steel produced by Selective Laser Melting (SLM) was reinforced with SiC nanoparticles using Friction Stir Processing (FSP). The microstructure and mechanical properties of the resulting nanocomposite were experimentally investigated, and multiscale finite element modeling was performed using the Mori-Tanaka homogenization method to predict its macroscopic mechanical properties based on microstructural interactions. SLM-fabricated samples were reinforced via FSP with 10 vol% SiC and subjected to tensile tests. Results showed a 17% increase in tensile strength for the solely FSP-processed sample compared to the as-built SLM sample (from 570 MPa to 670 MPa), with a slight improvement in ductility (from 27% to 29%). The addition of SiC nanoparticles further increased tensile strength to 743 MPa, while ductility decreased to 23%. This represented a 30% and 11% strength increase compared to the as-built SLM sample and the solely FSP-processed sample, respectively. The strength improvement was attributed to the dispersion of particles along grain boundaries and within grains, as well as to recrystallization and grain refinement induced by FSP. The stress-strain curves from finite element modeling aligned closely with experimental results. Predicted tensile strength and ductility were 668 MPa and 30% for the solely FSP-processed sample, and 740 MPa and 25% for the nanocomposite.