| Abstract Scope |
The mechanical performance of BCC multi-principal element alloys is closely linked to chemical ordering and subtle structural changes, which can be further amplified by oxygen interstitials. Capturing these effects and understanding their influence on strengthening and plasticity requires new approaches capable of resolving sub-nanoscale structural variations. By combining multidimensional diffraction methods, such as 4D-STEM, with spectroscopy and generative libraries of metastable structures, we identify nanoscale compositional undulations, strain localization, and early-stage transformation pathways. In this talk, I will focus on small-scale mechanical testing of Nb-rich Ti–Nb alloys with dilute oxygen additions of approximately 1 at.% as a model system to probe these effects. Our findings show that decomposition proceeds through Burgers-related intermediate phases along the BCC-to-α-HCP transformation pathway. We correlate these evolving structures with mechanical performance through strain heterogeneity, interfacial energy, morphology, and compositional undulations, providing new insights into the mechanical behavior of multi-component refractory alloys. |