Speaker
Description
Abstract
Cu-Fe Functionally Graded Materials (FGMs) can be developed by precise control over the materials’ composition and step-by-step chemical transition during additive manufacturing. This work includes the microstructural and mechanical behaviour of AISI 316L/Aluminium-Bronze FGM fabricated by Laser-based Directed Energy Deposition (DED-LB). Scanning Electron Microscopy (SEM), Electron Back-scattered Diffraction (EBSD), Transmission Electron Microscopy (TEM), and X-ray diffraction (XRD) techniques were used to discuss the evolution of the microstructure. Tensile and microhardness properties were investigated. The composition changed gradually, layer by layer, from Fe-rich to Cu-rich across the building direction, resulting in a continuous variation of microstructural features and mechanical properties. A largely refined grain structure including supersaturated solid solutions of Cu and Fe was observed. EBSD results showed a double phase, mixed fcc and bcc, textured material that was confirmed by XRD, too. However, the content of fcc phase is dominant at the ends, i.e., γ-Fe and ε-Cu phases. The α-Fe bcc phase, largely formed in the mid-section, was the product of Eutectoid transformation. Precipitation of globular and drop-shape islands of Fe-and Cu-enriched compounds was discussed by TEM results. These particles are formed and coagulated under the separation of melt induced by miscibility gap in Fe-Cu binary system and rapid solidification during DED-LB. Gradual decrease in tensile strength and micro-hardness behaviour were observed with increasing the distance from the austenitic steel side.
