F. Zhang, S. -. L. Chen, W. -. S. Cao, Y. Yang, K. -. S. Wu, CompuTherm, LLC, Madison, WI; Y. A. Chang, University of Wisconsin, Madison, WI
Phase diagrams are the foundation for performing basic materials research in many fields such as solidification, crystal growth, joining, phase transformation, and so on. They serve as a road map for materials design and process optimization since they are the starting point to understand the effects of alloy chemistry and heat treatment conditions on the final microstructure. Traditionally, phase diagrams were determined primarily by meticulous and costly experiments. While this approach has been both feasible and necessary for determining phase equilibria of binaries and those of ternaries over limited compositional regions, it is nearly impossible to use such an approach for the determination of phase diagrams of ternary and higher order systems over wide ranges of compositions and temperatures. Yet, most, if not all, commercial alloys are multicomponent systems.
In this presentation, we will demonstrate the significant progress made for the calculation phase diagrams of multicomponent alloys by the use of a phenomenological approach and its applications to aerospace materials, such as titanium alloys and nickel alloys. For the success application of this approach, two essentials are needed: one is robust computer software and the other thermodynamic databases for multicomponent alloys. In this presentation, we will present examples calculated by Pandat software and thermodynamic databases we have developed for nickel and titanium alloys. In the meantime, we will also demonstrate our efforts in integrating the phase diagram calculation with kinetic models to predict phase transformations and the microstructure evolution of these multicomponent alloys.
Summary: Phase diagrams are the foundation for performing basic materials research in many fields such as solidification, crystal growth, joining, phase transformation, and so on. In this presentation, we will demonstrate the significant progress made for the calculation phase diagrams of multicomponent alloys by the use of a phenomenological approach and its applications to aerospace materials, such as titanium alloys and nickel alloys.
