NiTi shape memory alloys (SMAs), as smart materials, are broadly used in medical implants and appliances despite the presence of toxic Ni. In this study, NiTiNb alloys were produced using the substitution of biocompatible Nb instead of Ni. The arc-melting method was utilized to make five SMA samples comprising Ni (29Àx) Ti 50 Nb (21+x ) (x = 0, 1, 2, 3, and 4); then, the phase transformation temperatures, microstructures, crystal structures, and chemical compositions were investigated by DSC, optical microscopy, XRD, and EDX measurements, respectively. The DSC results showed that the samples had a wide hysteresis with the B19¢MB2 phase transformation and martensite start temperatures below room temperature, which makes them suitable for superelastic implants. The presence of dissolved Nb in the matrix of the alloys was the main reason for the widening of temperature hysteresis. When the XRD and SEM results were examined, the b-rich, B2, B19¢, and Ti 2 Ni phases were observed in all samples. Additionally, the main constituent in the dendritic microstructures was Nb.

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It is aimed to investigate the coating of AISI316 stainless steel with NiCrBSi/WC at different ratios using TIG method. In this study, the Ni-based WC-reinforced MMC layer was manufactured by the TIG composite coating method, and then the microstructure of the coating layer was examined. Microstructure and phase components of the composite coatings were characterized by optical microscopy, scanning electron microscopy, and X-ray diffraction. A metallurgic bound was found between the coating layer and the substrate through the TIG coating process. WC was re-solidified in the matrix by dissolving with high input energy. Several phases were found, including Ni-rich ([Formula: see text]-Ni) primary dendritic phase, Ni-Ni3B, and Ni3Si eutectic structure, Cr7C3, Cr2B3, Cr3Ni2, Ni2W4C, and Ni[Formula: see text]W3 phases in dendritic structures. The presence of carbides in the structure had affected the hardness of the coating. The maximum hardness value was found to be 469.5 HV and the hardness of the coating layers was increased at least 2.5 times compared to that of the substrate material.