Gamma titanium aluminides

The first international symposium on gamma titanium aluminides (ISGTA) was held in conjunction with the TMS `95 Annual Meeting, 13--16 February 1995, Las Vegas, under the sponsorship of the TMS Structural Materials Division--Titanium Committee. The selected papers cover almost the entire aspects of the current gamma technology such as fundamentals, alloy development and design, process development, microstructure and property evaluation, and applications. The current status as well as the future of gamma titanium aluminide alloys are discussed, as an emerging engineering materials technology, including potential/real application areas of cast gamma alloys in turbine engines. The topics on environmental effects include oxidation resistance, coating, hydrogen effects and the effects of oxide scale on mechanical properties. Phase relations and transformations are discussed for alpha-phase decomposition, coarsening of lamellar structures, high temperature phase stability, and solidification. Deformation mechanisms are evaluated to explain the flow stress anomaly behavior. Deformation character, fracture behavior, fatigue and creep are evaluated for the lamellar structure of PST crystals. Advanced methodologies are evaluated for calculating the TiAl phase diagram as well as site preferences of various elements in the gamma phase. Studies on strengthening by solid solution as well as precipitation is reported. Measurements are reported of the solubilitiesmore » of oxygen and carbon as well as of the diffusivity and activation energies for various alloying elements in the gamma phase. Melting processes as well as methods for near-net-shaping are discussed. In summary, these proceedings confirm that gamma alloys are emerging as a new generation of structural materials. One hundred and two papers have been processed separately for inclusion on the data base.« less