A high-Nb TiAl alloy with highly refined microstructure and excellent mechanical properties fabricated by electromagnetic continuous casting

Abstract

In the present research,microstructure refinement of a high-Nb TiAl alloy (Ti-48Al-8Nb-0.15B) was realized by means of the electromagnetic continuous casting (EMCC) technique. The microstructure of an ingot obtained by EMCC was analyzed using scanning electron microscopy (SEM). As compared with the raw as-cast alloy,the obtained EMCC alloy presented a much finer microstructure with lamellar colonies with a mean size of about 50-70 μm because the electromagnetic stirring broke initial dendrites and enhanced the heterogeneous nucleation. As the grains were refined,the properties of the TiAl alloy were improved significantly. This implies that the EMCC technique could offer the possibility of application for high-Nb TiAl alloys with a refined microstructure and excellent properties to be used as a structural material.