Thermal stability and crystallization behavior of (Fe0.75 − xDyxB0.2Si0.05)96Nb4 (x = 0–0.07) bulk metallic glasses

Effects of Dy addition on the glass-forming ability (GFA), thermal stability, and crystallization behavior in (Fe0.75 − xDyxB0.2Si0.05)96Nb4 (x = 0–0.07) bulk metallic glasses (BMGs) were investigated. The thermal stability of the supercooled liquid was greatly improved by alloying with a small amount of Dy. The largest supercooled liquid region of 100 K was achieved for the x = 0.04 alloy, leading to the best GFA with a diameter of 4 mm. The activation energy for the first crystallization peak increased with the addition of Dy. However, adding more Dy may also increase the frequency factor and change the primary precipitation phase from Fe23B6 phase into DyFe11Si and DyFe3 phases, decreasing the thermal stability of the supercooled liquid. The possible relation between GFA and thermal stability, as well as crystallization behavior is discussed.

► BMGs with diameters up to 4 mm were synthesized in the FeDyBSiNb alloy system. ► Dy element enhances the formation of local CSRO in the supercooled liquid region. ► Crystallization behavior of the alloys is heavily dependent on the Dy content. ► The trend of GFA is related to the complexity of the structure of primary phase.