Soft magnetic and mechanical properties of Fe<SUB align="right">5Co<SUB align="right">4Ni<SUB align="right">4Cr<SUB align="right">1.5Al<SUB align="right">1Ta<SUB align="right">0.4Nb<SUB align="right">0.1 high

This study investigates the design and properties of a high-entropy oft magnetic alloy, specifically Fe5Co4Ni4Cr1.5Al1Ta0.4Nb0.1, synthesised through vacuum arc melting and subjected to various heat treatments, including solution treatment and ageing. The alloy's microstructure was thoroughly characterised using X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscope (SEM), revealing a single-phase face-centred cubic (FCC) structure with precipitated L12 coherent nanoparticles and other secondary phases. Mechanical properties were assessed through tensile tests and microhardness measurements, demonstrating a notable increase in yield strength and hardness following ageing, peaking at 917 MPa and 444 HV, respectively. The soft magnetic properties were evaluated using vibrating sample magnetometer (VSM), indicating a reduction in saturation magnetisation but an increase in coercivity with prolonged ageing. This research highlights the significance of controlled microstructural evolution and the precipitation strengthening mechanisms that contribute to the enhanced mechanical and magnetic characteristics of high-entropy soft magnetic alloys.