Actual Problems in Machine Building 2018 Vol. 5 No. 3-4

Actual Problems in Machine Building. Vol. 5. N 3-4. 2018 Materials Science in Machine Building ____________________________________________________________________ 102 enriched by Nb. Due to the adding of Nb the liquidus temperature is significantly increased. As a result, the Nb-rich β-Ti solid solution primarily precipitates at relative high temperature during solidification to form a dendritic phase. Such a β-Ti solid solution with bcc structure is expected to have very good ductility and low elastic modulus but also low strength. a b c d Fig. 1. OM Micrographs of a-b)Ti-30Nb and c-d) Ti-35Nb The results of the SX-Ray diffraction analysis of as-cast samples are plotted in Fig. 2. For the as-cast Ti-30Nb alloy bcc β phase was the dominating phase. A small amount of orthorhombic α`` phase also was detected. Due to the high intensity of the synchrotron radiation detection of the hexagonal ω phase is possible. When the alloying content is increased up to 35 % only β and ω phase were detected.