Effects of TiB2 and TiAl3 particles on refinement of cast structure of pure aluminum

Effects of TiB2 and TiAl3 particles, smaller than 15μ and 600μ, respectively, on grain refining of cast structure of 99.75% and 99.99% aluminum were studied. The results obtained are as follows:1) Grain size of cast aluminum decreased when 0.01 to 0.10%TiB2 was added. This effect became more pronounced as the particle size decreased. Further, it was found that the refinement effect due to TiB2 was more effective when the temperature of molten aluminum was raised to 900°C and 0.006%Ti was added in advance.2) Similarly, grain refining effect due to TiAl3 became more pronounced as the content of TiAl3 increased from 0.07% to 0.54% and the particle diameter decreased. This effect was further noted when the holding time and the temperature of the molten metal containing TiAl3 particles increased.3) When 0.05%TiB2 and 0.016%TiAl3 were added together to the molten metals, the refinement effect was very pronounced if the particle sizes of TiB2 and of TiAl3 were less than 2μ and 100μ, respectively. This observation was consistent with the refinement effect of the Al-5%Ti-1%B master alloy on the cast structure of pure aluminum.