Additive manufacturing of functional metallic parts based on layer-by-layer melting and solidification suffers from the detrimental effects of high-temperature processing such as large residual stresses, poor mechanical properties, unwanted phase transformations, and part distortion. Here we utilize the kinetic energy of powder particles to form solid-state bonding and overcome the challenges associated with the high temperature processing of metals. Specifically, we accelerated powders to supersonic impact velocities (~600 m/s) and exploited plastic deformation and softening due to high strain rate dynamic loading to 3D print Ti-6Al-4V powders at temperatures (800 °C, 900 °C) well below their melting point (1626 °C). By using processing conditions below the critical powder impact velocity and controlling the surface temperature, we created mechanically robust, porous metallic deposits with spatially controlled porosity (apparent modulus 51.7±3.2 GPa, apparent compressive yield strength 535±35, porosity 30±2%). When the mechanical properties of solid-state 3D printed Ti-6Al-4V were compared to other additive manufactured techniques, the Young's modulus was similar, but the compressive yield strength was up to 42% higher. Post heat treatment of solid-state printed porous Ti-6Al-4V modified the mechanical behavior of the deposit under compressive loading. Additionally, the 3D printed porous Ti-6Al-4V was shown to be biocompatible with MC3T3-E1 SC4 murine preosteoblast cells, indicating the potential biomedical applications of these materials. Our study demonstrates a single-step, solid-state additive manufacturing method for producing biocompatible porous metal parts with higher strength than conventional high temperature additive manufacturing techniques.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.