Consolidation of Cu- and Ti-based metal powders using layer-by-layer, spot pulsed electric current sintering

In this paper, we propose a technique for additive manufacturing of bulk materials from electrically conductive powders, based on the method of point wise electro pulse sintering. This method consists of layer-by-layer consolidation of powders, each layer being formed as a result of successive sintering of small portions of powder compressed between the electrode and the substrate, or between the electrode and the previously sintered layer. Using the proposed method, bulk samples were obtained from powders having the different chemical composition (Cu, Ti, mechanically alloyed tin bronze), and particles of various shapes (dendritic, dumbbell, stone-shaped). Using X-ray diffraction, electron microscopy, and micro hardness measurements, the structural phase states, and porosity of the obtained bulk consolidated materials were studied. Sintering of powders using this method is greatly influenced by the heat release along the boundaries of the particles, which in turn depends on the electrical resistivity of the material. The porosity of the sintered samples mainly depends on the type of powder used and decreases with the decreasing size of the powder particles. Keywords: additive manufacturing, electro pulse sintering, metal powders, porous structure