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Creep strength in polycrystalline Ni-based superalloys is influenced by the formation of a rich variety of planar faults forming within the strengthening γ' phase. The lengthening and thickening rate of these faults – and therefore the creep rate – depends on an intriguing combination of dislocation interactions at the γ/γ' interface and diffusional processes of the alloying elements at the core of the fault tip. The effect of alloy composition on this process is not fully understood. In this work we use correlative high resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy to study the deformation faults in two different Ni-based superalloys with carefully designed ratios of disordering-to-ordering-promoting elements (Co-Cr against Nb-Ta-Ti). The results show that the additions of ordering-promoting elements reduce the diffusional processes required for the faults to lengthen and thicken thus reducing the creep rates found for the higher Nb-Ta-Ti alloy. These insights provide a path to follow in the design of improved grades of creep-resistant polycrystalline alloys beyond 700 °C. 

Gendered differences in academic confidence and self-efficacy between men and women are well-documented. In STEM fields and specifically in engineering, such differences have important consequences in that students low on these constructs are often more prone to leave their degree programs. While this evidence base is fairly established, less is known about the extent to which men and women show differences in confidence of team success, or collective efficacy, which may also be consequential in decisions to join and persist in design team experiences, or even to stay in or leave an engineering major, especially for first-year students. In this analysis, we quantitatively investigated gendered differences in confidence of team success and collective efficacy among first-year engineering students working on semester-long design projects in stable teams. Using a software tool built to support equitable teamwork, survey data on team confidence and collective efficacy was collected for these engineering students as well as for students in other courses for the sake of comparison. Three hierarchical linear models were fit to the data from 1,806 students across 31 unique course/term combinations. The results were mixed. In two of these analyses, we identified significant interactions between gender and team confidence. Specifically, men generally reported higher team confidence scores than women throughout the term with women eventually catching up, and team confidence ratings increased for men but not women following a lesson on imposter syndrome. No gendered differences were observed with respect to a collective efficacy scale administered near the middle and end of the term, however. In all cases, the results were consistent across course type (engineering, business, and others). 

This work-in-progress paper reports on the assessment of an intervention on team communication and decision making processes to see whether such an intervention is related to improvement in the rating of equity of idea contributions. A hierarchical linear model was fit to teamwork data from 3,721 students in 40 courses. We find that students’ reports of equitable idea sharing are actually lower after the intervention than before; we hypothesize that the decreased rating might reflect increased student awareness of inequities rather than a true decrease in equitable idea sharing. This pattern held for most gender and racial groups, with the notable exception of non-binary students, who instead reported greater idea equity post-intervention, though we note the small sample size for this group. Finally, we find that decreases in reported idea sharing were largest when students reported the intervention was “highly relevant” to their team yet “not very helpful”.