https://hdl.handle.net/11256/2 Tue, 07 Apr 2026 04:50:50 GMT 2026-04-07T04:50:50Z https://hdl.handle.net/11256/1003 Calculated Collision Welding Process Windows in Acoustic, Elastic, and Shock Approximations Barnett, Blake Collision welding is a solid-state joining process which uses shock pressures developed during impact to metallurgically bond flyer and target plates. Various analytical expressions have been developed to describe the process boundaries for ideal welds in the welding velocity-impact angle plane. Existing process boundaries assume symmetric weld members, and/or symmetric post-impact weld behavior (stress partitioning and propagation velocities, peak temperatures, and cooling rates) which are not applicable to the majority of collision welding applications, which use dissimilar weld members. This work extends and modifies existing weld window boundaries through the application of elementary shock physics (Rankine-Hugoniot Relations) via discrete numerical calculations for permutations of weld pairs across approximately 30 elemental and alloy metals. Existing formulations of relevant process boundaries are also included for completeness. The MATLAB program used to generate the datasets and associated plots can be found on GitHub at: https://github.com/BBarnett-615/Collision-Welding-Process-Window-Calculator https://hdl.handle.net/11256/1003 https://hdl.handle.net/11256/998 Development of a Diffusion Mobility Database for Co-based Superalloys Campbell, Carelyn; Lindwall, Greta; Moon, Kil-won; Williams, Maureen; Tso, Whitney To facilitate the development of high-temperature Co-based gamma-gamma prime superalloys, a Co-Ni based diffusion mobility database is developed for the eight component FCC (Face Centered Cubic) system of Co-Al-W-Ni-Cr-Ti-Ta-Re. A CALPHAD approach is used to represent the temperature and composition dependency of the multicomponent system. The mobility descriptions are based on previous assessment work for the Ni-based superalloys, published experimental and computational data, and established diffusion correlations. The initial mobility descriptions were then refined using additional diffusion couple experimental data, particularly for the Co-Cr, Co-Ta, and Ni-Ta systems. After re-optimizing the descriptions with the new experimental data, the mobility descriptions were validated using a collection of published diffusion couple composition profiles, which were not included in the initial assessment process. https://hdl.handle.net/11256/998 https://hdl.handle.net/11256/994 Cubic crystal compounds - Jarvis DFT Kaundinya, Prathik This is the dataset of materials obtained from the Jarvis-DFT dataset and used for the study "Machine learning approaches for feature engineering of the crystal structure: Application to the prediction of the formation energy of cubic compounds". https://hdl.handle.net/11256/994 https://hdl.handle.net/11256/985 Thermodynamic analysis of the topologically close packed σ phase in the Co-Cr system Wang, Peisheng; Peters, Matthew C.; Kattner, Ursula R.; Choudhary, Kamal; Olson, Gregory B Density functional theory (DFT) calculations show that it is essential to consider the magnetic contribution to the total energy for the end-members of the σ phase. A more straightforward method to use the DFT results in a CALPHAD (Calculation of phase diagrams) description has been applied in the present work. It was found that only the results from DFT calculations considering spin-polarization are necessary to obtain a reliable description of the σ phase. The benefits of this method are: the DFT calculation work can be reduced and the CALPHAD description of the magnetic contribution is more reliable. A revised thermodynamic description of the CoeCr system is presented which gives improved agreement with experimental phase boundary data for the σ phase. Fri, 01 Nov 2019 00:00:00 GMT https://hdl.handle.net/11256/985 2019-11-01T00:00:00Z