熔体过热度对Nd9Fe85-xTi4C2Bx（x=10,12）磁性合金过冷度和非晶形成的影响

摘要

The effectsof melt overheating degree on the undercooling degree and resultant solidification structures of Nd9Fe85−xTi4C2Bx(x=10, 12) glass-forming alloyswerestudied by differential thermal analysis combining with solidification structure analysis. The results indicate that the undercooling degree of Nd9Fe85−xTi4C2Bx(x=10, 12) alloys significantly increaseswith the rise of melt overheating degree, and two overheating degree thresholds corresponding to the drastic increase of the mean undercooling degree are found for each of the alloys. The existence of two turning points of the mean undercooling degreescan be linked to the structure transitions inside the overheated melts, which result in the evident increase of volume fraction of amorphous phasein the solidified structures.%采用差热分析及凝固组织研究Nd9Fe85−xTi4C2Bx(x=10,12)合金熔体过热度对其过冷度以及凝固组织的影响。结果表明：Nd9Fe85−xTi4C2Bx(x=10,12)合金的过冷度随熔体过热度的增大而显著增大，且每种合金均出现两个对应于平均过冷度急剧增大的临界过热度。两个平均过冷度转折点的存在与过热熔体中的结构转变有关，这最终导致凝固组织中非晶相体积分数的增加。