TY - GEN A1 - Yasenchuk, Yuri A1 - Gunther, Victor A1 - Marchenko, Ekaterina A1 - Chekalkin, Timofey A1 - Baigonakova, Gulsharat A1 - Hodorenko, Valentina A1 - Gunther, Sergey A1 - Kang, Ji-hoon A1 - Weiß, Sabine A1 - Obrosov, Aleksei T1 - Formation of mineral phases in self-propagating high-temperature synthesis (SHS) of porous TiNi alloy T2 - Materials Research Express N2 - The complex structural-phase composition, morphology and elemental composition of surface and nonmetallics in porous TiNi compounds produced by self-propagating high-temperature synthesis (SHS) in a flow reactor in the layer-by-layer combustion mode were analyzed. The samples were investigated using light microscopy (LM), X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS). The findings indicate that in addition to the TiNi and Ti2Ni intermetallic constituents, the pore's surface contains numerous Ti4Ni2(O,N,C) nanocrystalline oxycarbonitrides, spinels, polysilicates, and residual amorphous phases. The elemental composition of the surface and crystalline inclusions is investigated by the EDS method. LM, SEM, TEM, and EDS instrumental examination revealed the entire surface comprising a continuous shell of intermetallic superficial bulb-shaped structures, as well as crystalline inclusions of polysilicates and spinels in the intergranular peritectic phase. Prominent morphology was confirmed to appear throughout the pore's surface owing to the interaction of the peritectic liquid (PL) with reaction gases. The epitaxial, nanocrystalline strata of intermetallic oxycarbonitrides were shown to have the intricate nature. Reaction gases chemisorbed by the PL are responsible for the continuous and dense substrate, which ultrafine structure modulates a high corrosion resistance. On the contrary, the sparse and foamy overlay resulted from a convective transfer of the PL by reaction gases facilitates in vivo bio-integration of the alloy. Overall, this sheds light on and may be more indicative of the complex role of superficial strata and nonmetallic crystals in enhanced biocompatibility of the unwrought porous TiNi alloy. KW - Porous TiNi alloys KW - SHS KW - Pore formation KW - Surface structures KW - Reaction gases KW - Amorphous layer Y1 - 2019 UR - https://iopscience.iop.org/article/10.1088/2053-1591/ab01a1 U6 - https://doi.org/10.1088/2053-1591/ab01a1 SN - 2053-1591 VL - 6 IS - 5 ER - TY - GEN A1 - Obrosov, Aleksei A1 - Yasenchuk, Yuri A1 - Marchenko, Ekaterina A1 - Gunther, Victor A1 - Radkevich, Andrey A1 - Kokorev, Oleg A1 - Gunther, Sergey A1 - Baigonakova, Gulsharat A1 - Hodorenko, Valentina A1 - Chekalkin, Timofey A1 - Kang, Ji-hoon A1 - Weiß, Sabine T1 - Biocompatibility and Clinical Application of Porous TiNi Alloys Made by Self-Propagating High-Temperature Synthesis (SHS) T2 - Materials N2 - Porous TiNi alloys fabricated by self-propagating high-temperature synthesis (SHS) are biomaterials designed for medical application in substituting tissue lesions and they were clinically deployed more than 30 years ago. The SHS process, as a very fast and economically justified route of powder metallurgy, has distinctive features which impart special attributes to the resultant implant, facilitating its integration in terms of bio-mechanical/chemical compatibility. On the phenomenological level, the fact of high biocompatibility of porous SHS TiNi (PTN) material in vivo has been recognized and is not in dispute presently, but the rationale is somewhat disputable. The features of the SHS TiNi process led to a multifarious intermetallic Ti4Ni2(O,N,C)-based constituents in the amorphous-nanocrystalline superficial layer which entirely conceals the matrix and enhances the corrosion resistance of the unwrought alloy. In the current article, we briefly explore issues of the high biocompatibility level on which additional studies could be carried out, as well as recent progress and key fields of clinical application, yet allowing innovative solutions. KW - porous SHS TiNi KW - biocompatibility KW - rheological similarity KW - corrosion resistance KW - bone substitution Y1 - 2019 UR - https://www.mdpi.com/1996-1944/12/15/2405/htm#B2-materials-12-02405 U6 - https://doi.org/10.3390/ma12152405 SN - 1996-1944 VL - 12 IS - 15 ER - TY - GEN A1 - Yasenchuk, Yuri A1 - Marchenko, Ekaterina A1 - Baigonakova, Gulsharat A1 - Gunther, Sergey A1 - Kokorev, Oleg A1 - Gunther, Victor A1 - Chekalkin, Timofey A1 - Topolnitskiy, Evgeniy A1 - Obrosov, Aleksei A1 - Kang, Ji-hoon T1 - Study on tensile, bending, fatigue, and in-vivo behavior of porous SHS-TiNi alloy used as a bone substitute T2 - Biomedical Materials N2 - Intermetallic porous SHS–TiNi alloys exhibit tangled and specific stress-strain characteristics. The article aims to evaluate the findings emanated from experiments using standard and proprietary instruments. Fatigue testing under repeated complex loading was used to measure the total number of load cycles to failure of SHS-TiNi samples. 70% of the tested samples, passed through 106 cycles without failure due to the reversible martensite transformation in the TiNi phase, one of the prevailing constituents of a multiphase matrix. The fractured surfaces were analyzed using SEM and confocal laser scanning instruments. Microscopic studies showed that the entire surface of the sample is concealed with the miscellaneous strata resulted from the SHS process, which effectively protect the porous alloy in a corrosive environment. Numerous non-metallic inclusions, which are also attributed to the SHS reaction, do not have a significant impact on the deformation behavior and fatigue performance. In this context, the successful in vivo functioning of porous grafts assessed in a canine rib-plasty model allows the bone substitute to be congruentially deformed in the body without rejection and degradation, having a long operational life, often greater than 17 million cycles. It acknowledges the potential benefits of SHS–TiNi as a superior osteoplastic material and its high resistance to corrosion fatigue. KW - porous TiNi KW - self-propagating high-temperature synthesis KW - fatigue strength KW - corrosion fatigue KW - biocompatibility Y1 - 2021 UR - https://iopscience.iop.org/article/10.1088/1748-605X/aba327/meta U6 - https://doi.org/10.1088/1748-605X/aba327 SN - 1748-605X VL - 16 IS - 2 ER - TY - GEN A1 - Gunther, Victor A1 - Yasenchuk, Yuri A1 - Chekalkin, Timofey A1 - Marchenko, Ekaterina A1 - Gunther, Sergey A1 - Baigonakova, Gulsharat A1 - Hodorenko, Valentina A1 - Kang, Ji-hoon A1 - Weiß, Sabine A1 - Obrosov, Aleksei T1 - Formation of pores and amorphous-nanocrystalline phases in porous TiNi alloys made by self-propagating high-temperature synthesis (SHS) T2 - Advanced Powder Technology N2 - The objective of this study was to examine the mechanism how the surface of porous TiNi compounds produced by SHS method evolves. The prepared samples were investigated using light-microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDS). The results indicated that the surface of all pores is represented by a granular stratum due to dendrite liquation by peritectic crystallization mechanism. The voids of 2–15 μm in size are formed owing to a capillary spreading of the liquid. Reaction gases with dissociated carbon, nitrogen, and oxygen are responsible for heat-and-mass transfer through the forming pores. High pressure-temperature effect of reaction gases on the melt causes the forming voids to coalesce, as well as transfers the peritectic liquid (PL) throughout the open pores catalyzing a distinctive spitted topography. It is through the chemisorption of gasiform nonmetallics by the pore surface melt, where these impurities are chemically bound, that it was formed a massive corrosion-resistant amorphous-nanocrystalline stratified shell deduced as an intermetallic oxycarbonitride layer. KW - Porous TiNi alloys KW - SHS KW - Pore formation KW - Surface structures KW - Heat-and-mass transfer Y1 - 2019 UR - https://www.sciencedirect.com/science/article/pii/S092188311830387X?via%3Dihub U6 - https://doi.org/10.1016/j.apt.2018.12.011 SN - 0921-8831 VL - 30 IS - 4 SP - 673 EP - 680 ER - TY - GEN A1 - Marchenko, Ekaterina A1 - Yasenchuk, Yuri A1 - Gunther, Sergey A1 - Baigonakova, Gulsharat A1 - Gunther, Victor A1 - Chekalkin, Timofey A1 - Weiß, Sabine A1 - Obrosov, Aleksei A1 - Dubovikov, Kirill T1 - Structural-phase surface composition of porous TiNi produced by SHS T2 - Materials Research Express N2 - The study aimed to characterize the structural-phase composition of the porous SHS TiNi surface explored by the GIXRD method. The surface layers at a depth of up to 100 nm mainly consist of amorphous nanocrystalline intermetallic oxycarbonitrides Ti₄Ni₂(O,N,C) with nonmetallic inclusions of different structural variants and routes of origin. Fine-porous alloys were synthesized at ignition temperatures of 450-480 °C. A distinct feature of the surface of crystalline phases therein was shown to be a low degree of crystallinity (up to 40%) and presence of multifarious glass and cermet phases evident as NiSi₂, NaAlSiO (SO₄), SiO₂, MgSi₂, and CaCO₃. Conversely, large-pore alloys ignited at temperatures of 280-330 °C have a higher degree of crystallinity (up to 70%). An individually selected GIXRD technique and precision structural phase analysis are capable to determine a set of other superficial nonmetallic and cermet phases reported as CaTiO₃, Si (P2O₇), CaSiO₃, MgAl₂O₄, TiNiAl, as well as the Ti₃SiC₂MAX phase. Y1 - 2019 UR - https://iopscience.iop.org/article/10.1088/2053-1591/ab4e32/pdf U6 - https://doi.org/10.1088/2053-1591/ab4e32 SN - 2053-1591 VL - 6 IS - 11 ER - TY - GEN A1 - Shtin, Valentin A1 - Novikov, Valeriy A1 - Chekalkin, Timofey A1 - Gunther, Victor A1 - Marchenko, Ekaterina A1 - Choynzonov, Evgeniy A1 - Baik Kang, Seung A1 - Jong Chang, Moon A1 - Hoon Kang, Ji A1 - Obrosov, Aleksei T1 - Repair of Orbital Post-Traumatic Wall Defects by Custom-Made TiNi Mesh Endografts T2 - Journal of Functional Biomaterials N2 - Repairs of orbital post-traumatic and extensive malignant defects remain a major surgical challenge, in view of follow-up outcomes. Incorrect surgical management of injured facial structures results in cosmetic, ophthalmic, and social aftereffects. A custom-made knitted TiNi-based mesh (KTNM) endograft was employed to overcome post-surgical complications and post-resected lesions of the orbital area. Preoperative high-resolution computed tomography (CT) imaging and CAD modelling were used to design the customized KTNM in each case. Twenty-five patients underwent surgery utilizing the suggested technique, from 2014 to 2019. In all documented cases, resolution of the ophthalmic malfunction was noted in the early period. Follow-up observation evidenced no relapsed enophthalmos, hypoglobus, or diplopia as late complications. The findings emanating from our clinical observations allow us to claim that the KTNM indicated a high level of biocompatibility. It is simply modified intraoperatively to attach any desired shape/size for implantation and can also be screw-fixed, providing a good supporting ability. The KTNM precisely renders orbitozygomatic outlines and orbital floor, thus recovering the anatomical structure, and is regarded as an attractive alternative to Ti-based meshes and plates. Additionally, we report one of the studied cases, where good functional and cosmetic outcomes have been achieved. KW - diplopia KW - enophthalmos KW - orbital defect repair KW - TiNi mesh Y1 - 2019 UR - https://www.mdpi.com/2079-4983/10/3/27 U6 - https://doi.org/10.3390/jfb10030027 SN - 2079-4983 VL - 10 IS - 3 ER -