Refining and Reinforcing Effects of In Situ AlN-TiN-iB(2)/Al Composite Refiner on Aluminum

Typical Al-Ti-B master alloys are good inoculant for aluminum alloys, which have shown obvious dependence on some alloying elements. In this work, in situ AlN-TiN-TiB2/Al composite refiner was successfully prepared by nitrogen alloying based on an Al-8Ti-1B melt. It is found that the refining, tensile strength, yield strength, and hardness of the pure aluminum modified by in situ AlN-TiN-TiB2/Al composite inoculant were all obviously improved. The enhanced refining and reinforcing effects of the refiner can be attributed to the following aspects: the formation of AlN and TiN particles, the homogeneous distribution of AlN, TiN, and TiB2 particles and the miniaturization of Al3Ti phases. The above three factors are all caused by nitridation and have a combining effect for improving the nucleation rate of alpha-Al.