Effects of Cu on Microstructures, Mechanical, and Magnetic Properties of Fe–Ni–P Alloys Fabricated by Liquid Phase Sintering

The Fe-Ni-P-Cu alloys with different copper content (0, 0.5, 1, and 2 wt%) are fabricated by liquid phase sintering (LPS) at 950 degrees C. The nano-Cu powder is mechanically mixed for 90 min with Fe-Ni-P composite powder using the ethanol as the medium. The microstructure, microhardness and compressive properties of Fe-Ni-P-Cu alloys are investigated. The results indicate that the copper is beneficial to improve the mechanical properties of sintered specimens. The sample contains a small amount of gamma-(Fe, Ni) phase when the copper content is 1 wt%, which results in its the highest compressive yield strength (948.1 MPa). The highest microhardness of 371 HV is accessible in Fe-Ni-P-Cu alloy with 2 wt% Cu. The fracture surface analysis indicates that sintered specimens with Cu addition exhibit a typical intergranular mode.