Effect of Al-Nb-Ti-B addition on microstructures, tensile mechanical and damping properties of AZ91 alloy

Al-Nb-Ti-B inoculant was added to Mg-9Al-1Zn (AZ91) alloy for the first time. MB2 particles with (TiB2)NbB2 core-shell structure in the inoculant have a good lattice matching relationship with AZ91 alloy, so they can be used as effective heterogeneous nucleation centers of the melt of AZ91 alloy, and lead to significant refinement of grains and microstructures. When the adding content of the inoculant reaches 0.8 wt%, the best refining effect can be achieved, and the average grain size is refined from the original 80.4 mu m to 18.2 mu m. With the decrease of grain size, the tensile strength, elongation and damping increase. Correlated mechanisms were discussed.

Automated summary

For the first time, Al-Nb-Ti-B inoculant was added to Mg-9Al-1Zn (AZ91) alloy. The MB2 particles in the inoculant with (TiB2)NbB2 core-shell structure have a good lattice matching relationship with AZ91 alloy, thus acting as effective heterogeneous nucleation centers of the melt of AZ91 alloy and leading to significant refinement of grains and microstructures. The best refining effect can be achieved when the adding content of the inoculant reaches 0.8 wt%, and the average grain size is refined from the original 80.4 μm to 18.2 μm. With the decrease of grain size, the tensile strength, elongation, and damping increase. The correlated mechanisms were discussed.