The kinetics of dendrite crystal growth in pure Ni and diluted Ni–B melts is analyzed. Using a model for anisotropic dendrites rapidly growing from undercooled melts, numerical solutions for dendrite tip velocity V and tip radius R are presented. The influence of boron content on tip velocity V and tip radius R of the dendrite growing in Ni-B alloys is shown in comparison with the growth kinetics of pure Ni–dendrites. Particularly, we show that there is a well-known regime of growth in which the impurity (boron) decreases the velocity of the alloying Ni–B–dendrite regarding the nickel dendrite velocity. In addition to this well-established regime, we also show quantitatively that there is a tiny amount of boron which enhances the dendrite velocity in comparison with the velocity of pure nickel dendrite. Explanations of this non-linearity are given using the results of calculations for dendrite tip radii and dendrite growth velocity for alloying Ni–B and pure Ni systems.

分析了纯镍和稀Ni-B熔体中枝晶生长的动力学。使用从过冷熔体快速生长的各向异性枝晶的模型，给出了枝晶尖端速度V和尖端半径R的数值解。硼含量对叶尖速度V和叶尖半径R的影响与纯Ni-枝晶的生长动力学相比，显示了Ni-B合金中枝晶的生长动力学。特别是，我们表明存在着一个众所周知的生长机制，其中杂质（硼）降低了与镍枝晶速度有关的合金化Ni-B-枝晶的速度。除了这种完善的机制之外，我们还定量地表明，与纯镍枝晶的速度相比，微量的硼会提高枝晶的速度。使用将Ni-B和纯Ni合金化的枝晶尖端半径和枝晶生长速度的计算结果，可以给出这种非线性的解释。