The effects of cold rolling and aging conditions on the microstructure and magnetic properties of a semi-hard Fe–Mo–Ni magnetic alloy

Abstract

Experiments were conducted to examine the effect of prior cold rolling and ageing conditions on the microstructure and magnetic properties of a ternary Fe–Mo–Ni magnetic alloy. For this purpose, a semi-hard Fe–18Mo–5Ni (wt. %) magnetic alloy was cold rolled at various reductions in area of 65, 80, and 95% for inducing the magnetic anisotropy. The cold rolled specimens were then aged at the various temperatures of 570, 610, and 640 °C for the different times of 1, 2, 3, and 6 h. The cold-rolled and aged specimens showed the crystallography texture as characterized by X-ray diffractometry method. The crystallography texture was described as the parallel orientation of the {002} family planes with the surface of rolling. The preferred orientation of {002} planes was intensified by cold-rolling, while it weakened by subsequent aging treatment. The coercive force was controlled in the range of 23–110 Oe by adjusting the ageing temperature and time due to the formation of the ferromagnetic (Fe,Ni)7Mo6 precipitates as revealed by optical and electron microscopy techniques. Furthermore, the magnetic measurements by vibrating sample magnetometer showed that the remanence and squareness increased from 0.94 to 1.2 T and from 0.58 to 0.77, respectively.