Effect of laser energy density on microstructure and properties Cu–Fe–P immiscible alloys fabricated by laser selective melting: heterogeneous and high strength and magnetic

Abstract

Through the incorporation of phosphorus (P) as a third component, an in-situ formation of a magnetic phase with a nanotwin structure was achieved. The utilization of selective laser melting (SLM) enabled the synthesis of a Cu–Fe–P immiscible alloy that exhibits an integrated structure and function. The microstructure predominantly consists of a magnetic heterogeneous Fe–P-rich phase, comprising a mixture of Fe2P and a small quantity of Fe3P, which is distributed within the ε-Cu Cu-rich matrix in alternating “fiber-layer” and “particle-shape” forms. Additionally, the fibrous Fe2P phase exhibited precipitation of α-Fe, while the Fe–P-rich phase experienced the precipitation of high-density nanotwinned Cu (nt-Cu) particles. The microstructure density and structural characteristics of Cu–Fe–P immiscible alloys were enhanced through the adjustment of laser energy density, leading to improvements in their mechanical and magnetic properties. It was observed that the microstructure density initially increased and then decreased with increasing laser energy density. The highest relative density of the Cu–Fe–P immiscible alloy microstructure (98%) was achieved at a laser energy density of 53 J/mm3. Furthermore, the influence of laser energy density on the mechanical and soft magnetic properties of Cu–Fe–P immiscible alloys was examined. The findings indicate that the mechanical and soft magnetic properties of these alloys are affected by the laser energy density. The findings indicate that the compact Cu–Fe–P immiscible alloys exhibit favorable compression mechanical properties and soft magnetic properties. Specifically, the ultimate compressive stress can reach 890.5 ± 20 MPa, while the failure strain can reach 20.5 ± 2%. Additionally, the coercivity is observed to be as low as 20.0 Oe, the magnetic saturation strength as high as 93.5 emu/g, and the residual magnetization at 1.1 emu/g.