Co3Cr, Co2Cr, and Co3Cr2, have been suggested to form from Introduction the e phase, as shown in Fig. 1b. The Co-Ti system (Fig. 2), taken from [Mass2] and origiThe Co-Cr-Ti system has been studied mostly near the nally assessed by [1987Mur], shows the presence of five Co corner where a ternary intermediate phase x, with a-Mn intermediate phases, Co3Ti, Co2Ti (h), Co2Ti (c), CoTi, and type crystal structure, has been found to exist. Two partial CoTi2, of which the Co2Ti (c) is a cubic Cu2Mg-type Laves isothermal sections, a few partial isopleths, and a liquidus phase and the Co2Ti (h) is a hexagonal MgNi2-type Laves projection have been reported for the Co corner. Only one phase. The CoTi phase melts congruently at 1325 8C, and isothermal section has been reported for the Cr corner of all the other phases form from the liquid through peritectic the Co-Cr-Ti system. Further investigation is required to reactions: L 1 CoTi } CoTi2 at 1058 8C, L 1 CoTi } Co2Ti establish proper phase equilibria for the complete Co-Cr(c) at 1235 8C, L 1 Co2Ti (c) } Co2 Ti (h) at 1210 8C, and Ti system. L 1 g } Co3Ti at 1190 8C. Two eutectic and one eutectoid reactions occur, L } Co2Ti (h) 1 Co3Ti at 1170 8C, L } a 1 CoTi2 at 1020 8C, and a } v 1 CoTi2 at 685 8C, where a and v are the bcc and hcp terminal solid solutions of (bBinary Systems Ti) and (a-Ti), respectively. The Cr-Ti system (Fig. 3), taken from [Mass2] and origiThe Co-Cr phase diagram in Fig. 1a is from the review nally reviewed by [1987Mur], shows an isomorphous system of [1990Gup] based on [1978All]. It shows a eutectic reaction with a minimum of 1408 8C at ,60 at.% Ti. Two Laves L } a 1 g at 1397 8C, where a and g are the terminal phases, cubic Cr2Ti (c) and hexagonal Cr2Ti (h) form from solid solutions of bcc (Cr) and fcc (Co), respectively. An the solid solution a phase at slightly different compositions. intermediate s phase forms from the bcc a solid solution The Cr2Ti (h) phase exists in two allotropic forms Cr2Ti (hh) congruently at 1283 8C. The fcc g phase transforms to hcp and Cr2Ti (hl), where hl and hl refer to the high-temperature e phase, terminal solid solution of hcp (Co), through a peritecMgZn2-type structure and low-temperature MgNi2-type toid reaction g 1 s } e at 967 8C. A eutectoid reaction a } g 1 s occurs at 1266 8C. Three more intermediate phases, structure which differ only in atomic layering. The Cr2Ti (hh)