Influence of annealing temperature and time on hysteresis parameters and microstructure of an Fe/Co/V alloy

The variations in coercivity, remanence, and microstructure for hour aging anneals between 300°C and 1000°C on an Fe/Co/3% V alloy have been determined. Additionally, the effects of varying aging times for temperatures between 885°C and 925°C have been analyzed. Hysteresis parameters and optical microstructures were characterized on wire samples which had been either cold worked by stamping or remained undeformed prior to the aging anneals. Results show that the alloy exhibits maximum magnetic hardness in its initial cold worked or undeformed conditions. Aging anneals produce a general decrease in magnetic properties with increasing temperatures to 700°C. However, the deformed material exhibits a secondary maximum for aging temperatures between 590°C and 610°C. For anneals above 800°C magnetic parameters again increase as a two-phased, duplex BCC (α1+ α2) structure is developed. By varying the aging time for anneals that produce this duplex structure, a level of coercivity comparable to that achieved for a 600°C anneal was attainable. However, a comparable level of remanence and, thus, a similar squareness ratio, could not be produced with the duplex structures developed by aging near 900°C.