Phase equilibria of 900, 1000, and 1100°C in the Co-Ti portion of the Co-Al-Ti system were mainly determined by energy dispersion x-ray spectroscopy. On the Ti-Al side, the β-Ti (A2) phase region is extended by the addition of Co and the βTi + AlTi3 (D019) two-phase region appears in the ternary equilibrium, while the AlTi (L10), AlTi3, and β-Ti phases show very low solubility of Co. It was found that the two ternary intermetallic compounds, Co2AlTi (L21) and CoAl2Ti (D8a), exist over a wide solubility range along the CoAl (B2)-CoTi (B2) and CoAl3-CoTi3 sections, respectively. The ordering transition and the phase separation due to ordering of the β-Ti, CoAl, or CoTi and Co2AlTi phases fundamentally possessing the bcc structure are also discussed.
ASJC Scopus subject areas
- Materials Science(all)
- Physical and Theoretical Chemistry
- Metals and Alloys