Experimental and theoretical dataset for 'Recycling of NiTi Shape Memory Alloys: Fundamental and Technological Aspects of a Vacuum Induction Melting Processing Route'

This dataset belongs to the publication "Recycling of Shape Memory Alloys: Fundamental and Technological Aspects of a Vacuum Induction Melting Processing Route", published in Advanced Engineering Materials on 15.05.26, DOI:10.1002/adem.202503197 (Preprint: DOI:10.5281/zenodo.17949492). This study deals with recycling of NiTi shape memory alloys via vacuum induction melting. An ingot was initially synthesized from elemental Ni and Ti and subjected to three remelting iterations. In this study, process durations and melt pool temperatures, chemical data, microstructural data obtained through scanning electron microscopy (SEM) imaging, data from thermal analysis, as well as data from thermodynamic considerations were evaluated. The corresponding raw data are provided in this repository. Material: Bulk Ni50Ti50 ingot, produced in a VIM furnace of type VSG 010 from PVA Tepla, remelted three times Casting: Molten metal was poured in a Y2O3-coated steel mold, yielding an ingot of cylindrical shape (diameter 40 mm, length 110 mm) with a conical pouring cup Sample: Samples for SEM imaging were extracted from the pouring cup in the as-cast state Metallographic preperation: Each SEM sample was mounted, grinded using SiC paper up to P2500 and polished with diamond suspension with particle sizes of 6, 3 and 1 µm Image acquisition: Scanning electron microscope of type LEO 1530 VP by Carl Zeiss AG in BSE mode with an accelerating voltage of 21 kV -------------------------------------- Attachments: "VIM Process data": Information regarding melt pool temperatues and melting durations during all melting stages and experiments. The raw data belong to Figure 8 in the original publication. "Ingot data": Data on evolution of trace element concentrations (C and O), martensitic transformation temperatures and TiC-type carbide area fractions. The raw data belong to Figure 9, 10e-f and 11 in the original publication. "BSE-SEM Micrographs": Compilation of selected BSE-SEM micrographs resolving microstructures of the NiTi ingot after each melting step. These micrographs show the martensitic matrix marterial with TiC-type carbides. The image diagonal (2560 px) corresponds to 71.2 µm. The raw data belong to Figure 10a-d in the original publication. "Enthalpies": Enthalpy values for all possible reactions occuring during Ni, Ti and NiTi (re)melting and mixing, as obtained by either novel atomistic calculations (GRACE) [1] [2] [3] [4] [5] or by CALPHAD. Thermo-Calc (vers. 2025.2) with the TCNi vers. 10.0 database was used for the calculations. The raw data belong to Figure 12a in the original publication. "Hmix": Composition-dependent enthalpies of mixing between 1500K and 2000K as obtained by GRACE. The raw data belong to Figure 12c in the original publication. "Thermocalc": Temperature-dependent enthalpy data for different phases considered in Figure 12b of the original publication ("Ni EQUILIBRIUM", "Ni LIQUID", "Ti EQUILIBRIUM", "Ti LIQUID", "NiTi EQUILIBRIUM", "NiTi LIQUID"), and data on the mixing enthalpy when mixing Ni and Ti at 1941 K ("Ni-Ti Mixing LIQUID 1941 K"). These raw data belong to Figure 12c in the original publication.