Ball milling nanocrystallization of arc-melted and melt-spun Fe78Co5Nb3Zr3B5Ge5Cu1 alloy:: microstructure and magnetic properties

The viability of developing a nanocrystalline microstructure for the Fe78Co5Nb3 Zr3B5Ge5Cu1 composition using a planetary ball mill was studied. Two starting samples were chosen: an arc- melted ingot and a partially crystallized melt- spun ribbon. The alpha- Fe phase was detected in both initial samples, although different intermetallic phases were detected in each of them. Milling at 150 rpm, these intermetallics disappeared after 5 h for the melt- spun alloy ( RQ) and did not disappear even after 70 h for the arc- melted sample ( AM). However, the alpha- Fe phase became nanosized in both cases. A good thermal stability was found for the RQ alloy after 10 h of milling, although the nanocrystal size increased from similar to 8 to similar to 20nm after heating to 973 K. The AM samples exhibited a lower coercivity and a higher magnetization than RQ samples.