Проницаемость пористых сплавов на основе никелида титана с добавками титана, полученных методом диффузионного спекания

Выполнено исследование структурных особенностей пористых сплавов на основе никелида титана с различной концентрацией добавки Ti, полученных методом диффузионного спекания. Определены параметры макроструктуры порового пространства сплавов TiNi–Ti – коэффициенты пористости и проницаемости, средний размер пор и межпоровых перемычек. Увеличение концентрации добавок Ti ведет к уменьшению средних размеров пор и увеличению средних размеров межпоровых перемычек. Исследованы коэффициенты проницаемости пористых материалов, полученных методами диффузионного спекания и СВС. Установлено, что коэффициенты проницаемости образцов, полученных разными методами, существенно отличались несмотря на схожие коэффициенты пористости. Это может быть объяснено тем, что экспериментальные образцы, полученные разными методами, имеют отличающуюся структуру поровых каналов: СВС-материал имеет регулярную взаимосвязанную пористую структуру, а спеченный материал – менее взаимосвязанные поры в продольном направлении, что в совокупности с малым размером пор затрудняет течение жидкости в материале

Получение биосовместимых пористых сплавов на основе никелида титана методами СВС и спекания

В статье рассматривается проблема получения сплавов на основе никелида титана (TiNi). Значительное внимание уделяется производству пористых проницаемых сплавов на основе TiNi. Существуют различные способы получения сплавов на основе TiNi, но многие из них требуют дорогостоящего оборудования, а также имеют недостатки, такие как продолжительность синтеза и получение недостаточно чистого продукта. Сегодня для получения пористых материалов широко используются методы самораспространяющегося высокотемпературного синтеза (СВС) и спекания, основным преимуществом которого является возможность получения пористых материалов с регулируемыми характеристиками структуры и физико-механическими свойствами. Поэтому целью данной работы является определение параметров СВС и спекания

The effect of cobalt additives on martensitic transformations and deformation in sintered porous nickel titanium alloys

Porous nickel titanium (TiNi) shape memory alloys with cobalt additives have been obtained by reaction and diffusion sintering. Analysis of the experimental temperature dependence of the electric resis tance and multiple shape memory effect leads to a conclusion that Co additives below 1 at % in reaction sin tered, and even more so in diffusionsintered, alloys lead to a reduction in intrinsic internal stresses in the TiNi phase. Additives above 1 at % induce dispersion hardening of the alloy. At all concentrations, cobalt additives lead to obstacles for the martensitic phase transformations

Reaction sintering of porous shape-memory titanium-nickelide-based alloys

The problems of reaction sintering of porous shape-memory Ti−Ni-based alloys are examined. An analysis of the structure and parameters of shape-memory materials produced with the use of different reaction sintering modes is performed. The temperature and time intervals are determined over which liquid-phase sintering points responsible for a qualitative change in the TiNi phase of the reaction-sintered Ti−Ni system are observed. The morphological structure and properties of the porous materials are investigated. Models for interactions between phases and phase transformations in the sintered alloys are built. It has been found that changes in the deformation parameters of the porous titanium nickelide-based alloys correlate with an increase in the volume fraction of the TiNi phase and with its wholeness as the sintering time is increased

Influence of cobalt and molybdenum additives on the structure and shape memory parameters of reaction-sintered porous nickel titanium alloys

We have studied the structure and properties of porous nickel titanium (TiNi) alloys obtained upon reaction sintering of Ti and Ni powders with Co and Mo additives. It is established that Co and Mo doping additives retain the compaction of Ni powder achieved at the initial stage of sintering. The maximum deformation of porous samples loaded in the austenite state was observed upon adding Co, while the addition of Mo resulted in minimum deformation. The addition of Co leads to single-stage martensitic transformation in TiNi phase, while the addition of Mo leads to the two-stage transformation that is more homogeneous over the volume. Both Co and Mo additives lead to increase in the maximum accumulated strain due to the formation of favorably oriented stress-induced martensite and reoriented quench-induced martensite

Production of two-dimensional porous TiNi-based powder material by diffusion sintering and electron-beam processing

The paper addresses the study of the surface condition of two-dimensional porous TiNi-based powder materials produced by diffusion sintering and electron-beam processing. Methods of production of two-dimensional TiNibased materials to be used for the purposes of non-destructive testing have been proven. The surface condition of the produced materials is described by scanning electron microscopy and interference profilometry

Investigation of the effect of copper addition on physical and mechanical properties of TiNi-Cu porous alloy

This work is devoted to the physical and mechanical properties of porous alloys based on TiNi alloyed with different amounts of Cu additive. We show that by doping a porous TiNi alloy with copper instead of nickel, it is possible to obtain characteristics acceptable for use in implantology and superior to those of known porous TiNi alloys. Cu addition in the range from 1 to 10 at.% is shown to optimize the properties of tested alloys. There is a decrease in the minimal martensitic transformation stress τminMs from 37 to 17 MPa when compared to initial unalloyed TiNi. Alloys with 3 and 6 at.% of Cu are found to be optimal for use in medical practice. Along with a wide temperature range of reversible deformations that cover the range of operating temperatures (273–313 K), such alloys demonstrate their martensitic transformation stress values below 28 MPs. This permits to model implantable structures of complex configuration from such materials under a certain temperature regime

Preparation of porous TiNi-Ti alloy by diffusion sintering method and study of its composition, structure and martensitic transformations

The study demonstrates a method for controlling not only the phase composition but also the atomic composition of TiNi matrix in porous TiNi-Ti alloys developed for biomedical uses as implants. The alloys were obtained from TiNi powder which was sintered with Ti powder added at as much as 0–10 at%. The structure, phase and chemical composition of the produced TiNi-Ti alloys was investigated with respect to the amount of Ti added into the material. It is shown that in the sintered product containing 5 at% and more of Ti additive, the composition of its TiNi matrix becomes close to equiatomic (with Ti:Ni atomic ratio ~1), and the excessive Ti precipitates as secondary phases Ti2Ni and Ti3Ni4. In parallel, with increase in Ti ad- ditive from 0–10 at%, the structure of the precipitating Ti2Ni type phases changes its morphology from separate spherical or pyramidal precipitates to large dendritic formations. The direct martensitic trans- formation from austenite to martensite in all the samples was found to proceed in two stages and through the R-phase (B2→R→B19′). Thermoresistive analysis demonstrated that TiNi-Ti samples with 5 and more at% of Ti had their characteristic starting temperature of martensite transition stabilizing at ~57 °C (330 K). This implies that the sample with 5 at% of Ti additive exhibited desired martensite transition temperatures, while containing a minimum concentration of secondary-phase precipitates in its matrix which deteriorate its properties. Thus, for the 곙rst time, we show that a very simple preparation approach based on sintering powders of TiNi and Ti is capable of producing porous TiNi-Ti alloys with properties optimized for fabricating bone implants

Aнализ бинарных диаграмм состояний на основе Ti-Ni-Mo

В статье проводится анализ диаграмм двойных систем Ti-Ni, Ti-Mo, Ni-Mo с целью создания коррозионно-устойчивых материалов на основе системы Ti-Ni-Mo для применения в технике. Рассмотрены фазовые продукты реакционного синтеза на основе порошковой системы Ti, Ni и Mo. Установлено, что к основным интерметаллическим соединениям относятся фазы: а-, в -Ti, Ti2Ni, Ti4Ni2O, TiNi, TiNi3, Ti3Ni4, Ti2Ni3, y-Ni, Мо (в], в2, а', а", ю-фазы), MoNi(S), MoNi3(y), MoNi4(e)