Microstructure and Magnetic Properties in Fe61Co9?x Zr8Mo5W x B17 (0 ≤ x ≤ 3) Glasses and Glass-Matrix Composites

摘要

By systematically investigating the Fe61Co9?x Zr8Mo5W x B17 (0 ≤ x ≤ 3) melt-spun ribbons and copper-mold cast cylinders with 2-mm diameter, we attempt to discover the effect of tungsten on the microstructure and magnetic properties of the Fe-based glass formers. It was found that all as-spun ribbons are fully amorphous and their characteristic distance δ a has an increasing tendency with tungsten content (c W). The precipitates in the as-cast cylinders change from the ferromagnetic phases (Fe23Zr6 + Fe2Zr + Fe2B + Fe8B) plus α-Fe to the nonmagnetic phases (ZrB12 + W2B5) plus α-Fe with increasing c W. The averaged characteristic distance δ c of the precipitates formed in the casting and annealing processes increases with c W, consistent with the δ a of the ribbons. The temperature and heat of the first crystallization for the as-prepared ribbons and cylinders (T p1 and ΔH 1) also increase with c W. The magnetization and Curie temperature of the as-prepared ribbons and cylinders decrease with c W, while the coercivity of the as-prepared samples is obviously dependent on the volume fraction of the precipitates formed in the casting process (CP). These results indicate that tungsten can tune the fractions of the face-centered-cubic/random-close-packed (fcc/rcp) and body-centered-cubic (bcc) Fe-rich structural units in the undercooled melts of the Fe-based glasses.