The research objectives are determination of the fundamental data on phase stability in intermetallic aluminides based on thermodynamic, mass transport and high temperatures environmental properties. The aluminide systems like Ti-Al, Nb-Al, Ni-Al and Fe-Al are selected based on their unique structural properties and practical significance. The thermodynamic data available in the literature are limited. Some of the phase diagrams are constructed based on limited experimental data. Initial experiments will be carried out on Ti-Al and Nb-Al binary and ternary systems. Compositions will be selected in the range of intermetallic phases like Ti₃Al, TiAl, TiAl₃, Nb₃Al, Nb₂Al, Nb₃Al and ternary additions like Mo, Hf and V will be added in the range of 5 to 25 atom percent. Alloys in this composition range will be equilibrated, analyzed for phase identification and tested for thermodynamic, mass transport and high temperature environmental properties. Thermodynamic properties will be determined using solid-state galvanic cells in the temperature range of 600 to 1000^oC, which is the expected temperature range of application for these alloys.