Evaluation of Different Sintering Agents for Binder Jetting of Aluminum Alloy

Recently, the automotive and aerospace industries have shown a growing interest to implement the binder jetting (BJ) on fabrication of lightweight aluminum products. However, the surface oxide layer on the aluminum particles presents a feasibility challenge as the thermal stability of the oxide layer often hinders the sintering. This study evaluates the effect of three different sintering agents including the oxide and metallic nanoparticles on the sintering of AlSi10Mg specimens. The sintering agents were introduced to the specimens using a polymeric binder to disrupt the oxide layer by locally infiltrating the powder layers. Microstructural characterization coupled with compositional analysis were used to examine densification and phase transformation. The specimens containing the alumina nanoparticles exhibited an incomplete sintering due to the undisrupted oxide layers. In contrast, the added copper oxide nanoparticle significantly enhanced densification by disrupting the oxide layer through a spinel formation. Among the considered sintering agents, the copper nanoparticle yielded sintered components with the greatest relative density (99.9%) by inducing liquid phase sintering.