Structure and Mechanical Properties of Porous TiNi Alloys with Ag Nanoparticles

The work studies the influence of the silver dopant (<0.5 at.%) on the structure and mechanical properties of porous TiNi alloys obtained by self-propagating high-temperature synthesis. These alloys are of high scientific and practical interest in medicine. The presence of silver in the TiNi alloy will ensure improved cytocompatibility and antibacterial properties. The TiNi porous alloys with 0.2 and 0.5 at.% Ag nanoparticles have multiphase composition. Quantitative X-ray diffraction analysis of the obtained alloys showed that an increase in the silver content is accompanied by a quantitative decrease in the austenite phase TiNi(B2) and an increase in the martensite phase TiNi(B19’), as well as in secondary phases Ti2Ni, Ti4Ni2O. Evenly distributed silver nanoparticles up to 10 nm were found in the surface layer by transmission electron microscopy. The results of the scanning electron microscopy showed that inclusions containing silver are located mainly in the zones of Ti2Ni peritectic crystallization. The mechanical characteristics were studied by means of compression tests and it was found that with an increase in the silver dopant, the elastic modulus and elastic limit decrease, but the maximum deformation to fracture increases significantly. It was found that with an increase in the volume fraction of silver, the plastic properties of the alloy increase. No dependency of the tensile strength on the amount of silver was found.