Undercooled Solidification of Ni-3.3wt.%B Alloy

Ni-3.3wt.%B alloy solidified at different undercooling by glass fluxing has been studied. The as-solidified structure is mainly controlled by the undercooling for eutectic solidification, ΔT2, instead of ΔT1, the undercooling for primary solidification. For ∆T22 ≥145±5K, three recalescence peaks appear in cooling curves. If ∆T22≥145±5 K, two kinds of dot phases occur. Further analysis declares that, the regularly distributed dot phases with larger size come from the transformation L→Ni23B6+Ni, whereas, the irregularly distributed ones with smaller size come from Ni23B6→Ni3B+Ni. Both of them have a contribution to strengthen the mechanical property.