TiB₂粒子尺寸分布对 Al-5Ti-1B 晶粒细化效果的影响

As the main phase contributing to grain refinement in Al-5Ti-1B，the size distribution of TiB₂ plays a vital role in determining the grain refining effect. The problems of broad size distribution interval and difficulty to control and adjust particle size distribution existed in the conventional Fluoride method were overcomed by adding ex-situ TiB₂ to prepare Al-5Ti-1B with controllable TiB₂ size，and the influence of TiB₂ particle size distribution on grain refining effect of Al-5Ti-1B on pure Al was investigated by combining refining experiment and model calculation. The results indicate that under the conditions of 0.2% TiB₂ addition and a cooling rate of 1.5 ℃/s，the grain refining effects of Al-5Ti-1B prepared by adding TiB₂ with a median particle size of 2.5 μm and 1.4 μm reach 149.2 μm and 137.0 μm，which are reduced by 46% and 50% compared with that obtained from Al-5Ti-1B prepared through conventional fluoride method，respectively. It is beneficial for further improving the grain refining effect of Al-5Ti-1B to adjust the size distribution of TiB₂ towards a finer and more concentrated direction.