Materials Engineering Department
BS in Materials Engineering
The goal of this project was firstly to characterize Cal Poly’s SLM printed 316L stainless steel. SEM analysis showed Cal Poly’s as-printed 316L material to have a cellular dendritic microstructure containing mostly austenite and a small amount of δ-ferrite. After being heat treated to eliminate warp, its yeild and ultimate tensile strength were on par with the literature, however higher modulus and lower elongation were observed. XRD analysis confirmed residual stresses in the material, and that grains are preferentially oriented in both heat treated and non heat treated samples. The amount of porosity in the material was found to be about 0.93%, and the material experiences ductile fracture. The second part of the project was to test four different microlattice geometries in uniaxial compression, the octet truss was the most efficient geometry having the highest specific stiffness.