Ti-Zr-Nb based BCC alloy containing Mo prepared by laser directed energy deposition-ω phase and cellular structure

Abstract

This study focuses on the fabrication of Ti-Zr-Nb beta-Ti alloys via laser direct energy deposition (DED) technique using pre-alloyed powder with and without having Mo traces. Microstructural analysis revealed the presence of cellular structures within the grains, resembling dendritic solidification, although no discernible dendritic segregation was observed. Nano-scale solute element clustering, particularly the formation of Nb depletion pockets, led to the development of the omega phase within the beta matrix. Strengthening effects resulting from the presence of the omega phase were confirmed through TEM analysis. The DED-fabricated beta-Ti alloy exhibited enhanced strength (-1 GPa), significant elongation (-15%), and a low elastic modulus (-65 GPa), positioning it as a promising candidate for load-bearing biomedical implants.