The Effect of TiB<sub>2</sub> Particles on the Microstructure of Semi-Solid 7075 Alloy Slurry

In situ reaction and low superheat degree pouring technologies have been successfully used to prepare semi-solid TiB2/7075 aluminum matrix composite slurry. The experimental results have shown that the TiB2 particulates become the stable nucleus of α-Al during the solidification of 7075 Al alloy. Moreover, high speed impact formed in the serpentine channel and stainless steel beaker is beneficial to get fine globular grains. The microstructure of 3 mass%TiB2/7075 composite is composed of uniform globular grains. The mean grain sizes and shape factors of the composite are 23 µm, 0.90 and 26 µm, 0.89 at 655°C pouring temperature when one or two curved channels were used respectively.