Design Guidelines for High Strength Multicomponent Alloys

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A new class of alloys called "High Entropy Alloys" is emerging as candidate materials for high strength applications. These alloys have very complex chemistries and are composed of a large number of elements. The processes by which they deform are also complex. This award supports research to understand deformation and fracture behavior of these alloys. The researchers seek to understand how the complex composition of these materials can be used to advantage the search of high strength and ductile alloys. By varying different compositional and processing parameters, it is expected that useful criteria may be found to optimize the combination of strength and ductility. The research will be incorporated in curriculum development for the education of future generations of researchers that are trained to use these computational tools in combination with experiments. The project contributes to the education of high school and undergraduate students through web educational modules used in undergraduate and graduate courses, summer camps, and internships. These instructional materials are geared particularly for female students to encourage their participation in this field. This research effort is based on the hypothesis that by varying atomic interaction parameters, useful criteria can be found to optimize the combination of strength and ductility. Because of limitations in the number of atoms that can be studied using first principle calculations, the researchers will utilize simple model interaction potentials for various degrees of variation in atomic sizes, cohesive energies, and chemical interaction. They will obtain trends in strength and fracture toughness as a function of these varying degrees of complexity. These trends will be compared with available experimental studies of the mechanical behavior of various high entropy alloys that indicate increased ductility while maintaining high strength. The methodology developed here for model interactions provides a basis for future computational modeling. Most importantly, the insight provided by this work enable more efficient design of single-phase high entropy alloys for a variety of applications.