A novel fading-resistant Al–3Ti–3B grain refiner for Al–Si alloys

Al–Ti–B refiners with excess-Ti perform adequately for wrought aluminum alloys but inefficiently in the case of foundry alloys. The high content of silicon in the latter, which forms silicides with Ti and severely impairs the refining potency of the nuclei, is known to be responsible for the poor performance. Hence, new grain refiners, such as Al–3B and Al–3Ti–3B master alloys with excess-B have been developed with well documented advantages for Al–Si alloys. It is very desirable to involve TiAl3 particles in the Al–3Ti–3B master alloy to maximize its grain refining efficiency. However, fading phenomenon is a key drawback for application of the TiAl3-containing refiners in aluminum foundry. In the present work, new Al–3Ti–3B grain refiners, containing TiB2, AlB12 and TiAl3 particles were developed with an aim to prolong the acting time after inoculation. The results showed that inoculation of Al–7Si alloy with thus meliorated Al–3Ti–3B grain refiner has produced a fine grain structure which was approximately maintained up to 30 min.

► A novel Al–3Ti–3B refiner for Al–Si alloy was produced via the halide salt route.
► The novel grain refiner is superior to the conventional Al–3B master alloy.
► TiAl3 in the master alloy results in fast acting.
► AlB12 particles lead to fading-resistant nature of the refiner.