| Abstract Scope |
During his brilliant career, Professor Nix made significant contributions to our understanding of high temperature deformation of materials, and inspired generations of researchers to the field. This presentation will provide examples for which advanced electron microscopy characterization has elucidated important dislocation-level phenomena associated with high temperature deformation. Jogged-screw dislocations are a commonly observed feature in a variety of alloys: TiAl, Ti alloys, and bcc alloys, including refractory high entropy alloys. The reasons that this rate-limiting process occurs in this diverse group of alloys will be discussed. Local phase transformations occur dynamically at stacking faults/twins in superalloys, and this finding provides new routes to strengthening at high temperature. Finally, additive manufacturing creates new opportunities for producing creep-resistant oxide dispersion strengthened (ODS) alloys. The substructural source for the strengthening by oxides will be discussed, and the potential for additive ODS fcc alloys and superalloys will be presented. |