Improvement of magnetic properties and hardness by alloying Mo to a FeCrCo alloy

Abstract

In most of the technologies used for improving material properties, the enhancement of some properties usually leads to the degradation of others. In this study, we demonstrated that we were able to simultaneously improve hardness, coercivity, and remanence by alloying an FeCrCo alloy with Mo by engineering its α → α₁ + α₂ spinodal decomposition. We prepared six Mo-alloyed samples and subjected them to the appropriate aging protocols. As aging progressed, hardness increased from 272 to 447 HV and coercivity increased from 47 to 592 Oe in the alloyed samples. Remanence gradually increased from 52 to 98 Am²/kg, and then decreased to 82 Am²/kg in the final stage of the aging process. By adding Mo to six individual FeCrCo samples aged to different stages, we increased the hardness of these samples by 3 %, 8 %, 7 %, 8 %, 5 %, and 10 %, respectively. At the same time, we increased their coercivity by 74 %, 13 %, 19 %, 4 %, 14 %, and 9 % respectively and their remanence by 82 %, 63 %, 4 %, 4 %, 9 %, and 13 %, respectively. We used data drawn from scanning transmission electron microscopy, first-principles calculations, and magnetic force microscopy in order to elucidate the reasons behind the observed enhancements of magnetic properties in the FeCrCoMo alloy.