Microstructure and properties of Ti–Zr congruent alloy fabricated by laser additive manufacturing

Abstract In the present work, Ti40Zr (atomic percent) congruent alloy, as well as four other Ti–Zr alloys near the congruent point, was fabricated using laser additive manufacturing (LAM) on pure titanium substrate. Comparative analyses of these alloys were performed based on microstructure, mechanical properties, tribological properties, corrosion resistance, and formability. The results show that the microstructure of the alloys develops sequentially from the Widmanstatten structure to nearly full β-(TiZr) columnar crystals for 40 at.% Zr, to β-(TiZr) columnar crystals plus granular α-(TiZr) with the increase of Zr addition. The Ti60Zr40 congruent alloy with nearly full β-(TiZr) structure presents a novel combination of ductility, corrosion resistance, and formability, but it has a slightly lower hardness, less strength and poor tribological properties, compared with the other Ti–Zr alloys near the congruent point. Therefore, to develop the congruent alloy as a high strength LAM material through alloying is very significant.