2016 年 57 巻 8 号 p. 1266-1271
The microstructural evolution of a NdFeB starting alloy fabricated by a strip-casting method was investigated as a function of the surface roughness, surface velocity, and thermal conductivity of the cooling roll of the strip caster. The nucleation of the solid phase took place preferentially at the edges of grooves machined on the roll and the grain size was inversely proportional to the frequency of nucleation. A higher surface velocity produced thinner strip-cast samples. The growth rate of the solid phase weakly influenced the dendrite sizes compared with the case of a thin plate obtained using mold-casting. Cooling rolls with higher thermal conductivity resulted in alloys with smaller grain and dendrite sizes.
