Influence of Intensive Plastic Deformation on Properties of Hard Magnetic Alloy Fe-30% Cr-20% Co-2% Mo

In this work, samples of the Fe-30%Cr-20%Co-2%Mo hard magnetic alloy were obtained and studied using powder metallurgy methods. Unlike the known scheme for fabricating powder hard magnetic materials, which includes sintering, quenching and subsequent multi-stage heat treatment, the ECAP (equal-channel angular pressing) operation was added to the process. The ECAP stage was added between the quenching and heat treatment stages. The obtained results demonstrated the possibility of using ECAP for processing hard-to-deform powder hard magnetic alloy. The workpieces retain their integrity with one pressing in the temperature range of 200–400 °C. Three-fold pressing at 300 °C does not damage the integrity of the workpieces, but at 400 °C the workpieces are destroyed into separate fragments. Hardness studies of the workpieces after ECAP showed non-uniformity of mechanical properties across the sample cross-section, and the presence of significant residual stresses was detected. Average hardness values increase with an increase in ECAP temperature from 200 to 400 °C. The magnetic properties of the alloy decrease when the ECAP stage is added. Re-quenching after the ECAP process almost completely erases its effects and returns the magnetic properties to the level of the material properties without its use.