Calculation of activity coefficients for components in ternary Ti alloys and intermetallics as matrix of composites
(1. State Key Laboratory for Mechanical Behavior of Materials, College of Materials Science and Engineering, Xi’an Jiaotong University,
Xi’an 710049, China;
2. Department of Materials Science and Engineering,
Northwestern Polytechnical University, Xi’an 710072, China;
3. College of Environment and Chemical Engineering, Xi’an University of Engineering Science and Technology, Xi’an 710048, China)
Xi’an 710049, China;
2. Department of Materials Science and Engineering,
Northwestern Polytechnical University, Xi’an 710072, China;
3. College of Environment and Chemical Engineering, Xi’an University of Engineering Science and Technology, Xi’an 710048, China)
Abstract: Based on Kohler’s ternary solution model and Miedema’s model for calculating the formation heat of binary solution, the integral equation was established for calculating the activity coefficients in ternary alloys and intermetallics. The activity coefficients for components in alloy Ti-5Al-2.5Sn, Ti-6Al-4V and intermetallics TiAl, Ti3Al and Ti2AlNb were calculated with the equations. The calculated data coincide well with the experimental ones found in literatures. According to the calculated activity coefficients and activities, it can be predicted that the interfacial reaction in SiC/Ti3Al composite is more severe than that in composites SiC/Ti2AlNb and SiC/TiAl.
Key words: activity coefficient; thermodynamics; Ti-alloy; intermetallics; interfacial reaction