Effects of Ta content on phase transformation in selective laser melting processed Ti-13Nb-13Zr alloy and its correlation with elastic properties

The phase transformation (beta ->omega and omega ->alpha+beta) and its correlation with the elastic properties of the selective laser melting (SLM) processed Ti-13Nb-13Zr-[0-8]Ta (wt.%) alloys were investigated. Analysis of the omega phase formation revealed that when the content of Ta is less than 6%, the formation of omega phase increases with the increase of Ta content in the alloys, while the high content of Ta (8 wt%) suppresses the omega phase formation. The elastic modulus of the alloys increases first and then decreases with the increase of Ta content due to the subsequent changes in the amount of omega phase. However, the omega phase is decomposed into alpha and beta phases after solution treated and the elastic modulus of the alloys is decreased with the increase of Ta. Furthermore, the orientation relationship of O' phase with beta phase was discussed by black field transmission electron microscopy and selectedarea electron diffraction.