Abstract Scope |
Metallic foams can provide tailored thermal management, absorb impact energy, and enhance the adhesion or biocompatibility of surfaces. In additive manufacturing (AM), lattice structures are the typical means to tune effective material density and therefore mimic these effects. Yet, intentionally incomplete fusion of powder feedstock in laser melting, or the addition of foaming agents can result in finely tuned porosity with cell sizes smaller than typical architected lattice structures. We are developing a hybrid AM process, whereby inkjet printing is used to spatially deposit additives prior to laser melting. Here, we study the ability to locally control subsurface pore size and density within 316L stainless steel using a polymer foaming agent. Etched metal plates are used for single-layer print studies to assess the influence of polymer concentration, laser power, hatch spacing, and scan speed; results are related to a simplified thermal model of the heating and cooling rates during LPBF. |