ENHANCEMENT OF STRENGTH PROPERTIES IN BIOCOMPATIBLE Ti-Nb-Zr ALLOYS BY SEVERE PLASTIC DEFORMATION

Перспективным направлением развития производства медицинских имплантатов из биоинертных материалов является создание сплавов с низким модулем упругости, полученных методами интенсивной пластической деформации (ИПД). В исследуемых образцах из прутков плавки 92 (Ti-40Nb-5Zr) и плавки 94 (Ti-40Nb-5Zr-2Ta-2Sn) после интенсивной пластической деформации методом abc-прессования с последующей прокаткой установлено повышение предела прочности по сравнению с исходным состоянием после горячей прокатки с 620 до 940 Мпа и с 610 до 760 МПа соответственно. Изготовлен образец и методом ДМА определена зависимость модуля упругости от температуры нагрева в диапазоне от комнатной до 600 °С.A promising direction in the development of the production of medical implants made of bioinert materials is the creation of alloys with a low elastic modulus, obtained by severe plastic deformation (SPD) methods. In the studied samples from rods of melt 92 (Ti-40Nb-5Zr) and melt 94 (Ti-40Nb-5Zr-2Ta-2Sn), after severe plastic deformation by the abc-pressing method followed by rolling, an increase in ultimate strength was found compared to the initial state after hot rolling from 620 to 940 MPa and from 610 to 760 MPa, respectively. A sample was made and the dependence of the elastic modulus on the heating temperature in the range from room temperature to 600 °C was determined using the DMA method.Исследование выполнено при финансовой поддержке Министерства науки и высшего образования Российской Федерации в рамках Программы развития Уральского федерального университета имени первого Президента России Б.Н. Ельцина в соответствии с программой стратегического академического лидерства «Приоритет-2030»

SEQUENCE OF PHASE TRANSFORMATIONS IN THE Ti-6Al-4V ALLOY UPON COOLING FROM THE Β-REGION

В настоящей статье представлены результаты исследования последовательности фазовых превращений в сплаве Ti-6Al-4V при охлаждении на воздухе после термической обработки в β-области. Исследования основаны на анализе микроструктурных характеристик, полученных методами просвечивающей электронной микроскопии (ПЭМ) и энергодисперсионной рентгеновской спектроскопии (ЭДС). В результате исследования было сделано предположение, что распад в сплаве Ti-6Al-4V при охлаждении на воздухе происходит в следующей последовательности: 1) при Тпп высокотемпературная β0-фаза претерпевает распад на α1- и β0-фазы, которые в процессе охлаждения изменяют свой химический состав, преобразуясь в α2- и β1-фазы, химические составы которых существенно отличаются от исходных; 2) при температуре нонвариантного превращения происходит преобразование β1-фазы в α3- и β2-фазы, с выполнением ориентационных соотношений Бюргерса.This paper presents the results of an investigation into the sequence of phase transformations in the Ti-6Al-4V alloy during air cooling after heat treatment in the β-region. The research is based on the analysis of microstructural characteristics obtained through Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDS). As a result of the study, it is hypothesized that the phase transformatin in the Ti-6Al-4V alloy upon air cooling occurs in the following sequence: 1) at the β-transus temperature, the high-temperature β₀-phase undergoes decomposition into α₁- and β₀-phases. During cooling, these phases modify their chemical compositions, transforming into the α₂- and β₁-phases, which chemical compositions significantly differ from the parent ones. At the non-variant transformation temperature, the β₁-phase is transformed into the α₃- and β₂-phases according to the Burgers Orientation Relationships

Inhomogeneity of deformed state during compression testing of titanium implant

This study examines the inhomogeneity of deformed state during compression testing of porous titanium implant. The theoretical part of the article includes numerical simulation of deformation of a prismatic titanium sample compressed with absolutely rigid plates. The porosity was provided by the circular shape pores with titanium struts between them. To solve the problem by means of the finite element analysis, the boundary conditions were set using the ABAQUS software. The fields of strain, stresses and displacements were determined. Presumable place of fracture coincide with the highest values of strain which are localized in vertical struts. Physical modeling of the implant compression was performed at the second part of the study on the testing machine with video recording. It was shown that in the real process the localization of failure corresponds to the calculated data

Inhomogeneity of deformed state during compression testing of titanium implant

This study examines the inhomogeneity of deformed state during compression testing of porous titanium implant. The theoretical part of the article includes numerical simulation of deformation of a prismatic titanium sample compressed with absolutely rigid plates. The porosity was provided by the circular shape pores with titanium struts between them. To solve the problem by means of the finite element analysis, the boundary conditions were set using the ABAQUS software. The fields of strain, stresses and displacements were determined. Presumable place of fracture coincide with the highest values of strain which are localized in vertical struts. Physical modeling of the implant compression was performed at the second part of the study on the testing machine with video recording. It was shown that in the real process the localization of failure corresponds to the calculated data

Structure, phase composition, physical properties of quenched VT16 alloy

Features of structural and phase composition, physical and mechanical properties formation of VT16 alloy during quenching from temperature range 700-875°C were determined. For the first time formation of athermal ω-phase during quenching of the VT16 alloy within initial (α+β)-structure was experimentally shown. According to the summarized XRD and TEM data diagram of volume fraction variation depending on quenching temperature was proposed. Minimum of yield strength in the certain quenching temperature range was confirmed to be connected with the behavior of martensitic β → α″-transformation during tensile testing. Fine correlation between the Young's Module and phase composition variation was shown

Monoclonal antibody therapy efficacy can be boosted by combinations with other treatments: Predictions using an integrated Alzheimer’s Disease Platform

Abstract For many years, clinical research in Alzheimer’s disease (AD) has focused on attempts to identify the most explicit biomarker, namely amyloid beta. Unfortunately, the numerous therapies that have been developed have failed in clinical practice. AD arises as a consequence of multiple factors, and as such it requires a more mechanistic analytical approach than statistical modeling. Quantitative systems pharmacology modeling is a valuable tool for drug development. It utilizes in vitro data for the calibration of parameters, embeds them into physiologically based structures, and explores translation between animals and humans. Such an approach allows for a quantitative study of the dynamics of the interactions between multiple factors or variables. Here, we present an overview of the quantitative translational model in AD, which embraces current preclinical and clinical data. The previously published description of amyloid physiology has been updated and joined with a model for tau pathology and multiple intraneuronal processes responsible for cellular transport, metabolism, or proteostasis. In addition, several hypotheses regarding the best correlates of cognitive deterioration have been validated using clinical data. Here, the amyloid hypothesis was unable to predict the aducanumab clinical trial data, whereas simulations of cognitive impairment coupled with tau seeding or neuronal breakdown (expressed as caspase activity) matched the data. A satisfactory validation of the data from multiple preclinical and clinical studies was followed by an attempt to predict the results of combinatorial treatment with targeted immunotherapy and activation of autophagy using rapamycin. The combination is predicted to yield better efficacy than immunotherapy alone

The effect of thermal treatment on the properties of SLM samples with a bionic design

This article shows the possibility of additive technology applied to medical implants. It’s shown the difference of physical properties such as elastic module of bones, implants made of traditional technology and implants made of additive technology. Porous structure has been chosen for future implants through designing its and further calculation of its mechanical properties using software such as Solid Works, Logos and Ansys. To confirm the right choice of design of structure we manufactured samples with using Rosatom 3D printer, made heat treatment and tested them

A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti2AlNb

Titanium alloys based on orthorhombic titanium aluminide Ti2AlNb are promising refractory materials for aircraft engine parts in the operating temperature range from 600–700 °C. Parts made of Ti2AlNb-based alloys by traditional technologies, such as casting and metal forming, have not yet found wide application due to the sensitivity of processability and mechanical properties in chemical composition and microstructure compared with commercial solid-solution-based titanium alloys. In the last three decades, metal additive manufacturing (MAM) has attracted the attention of scientists and engineers for the production of intermetallic alloys based on Ti2AlNb. This review summarizes the recent achievements in the production of O-phase-based Ti alloys using MAM, including the analysis of the feedstock materials, technological processes, machines, microstructure, phase composition and mechanical properties. Powder bed fusion (PBF) and direct energy deposition (DED) are the most widely employed MAM processes to produce O-phase alloys. MAM provides fully dense, fine-grained material with a superior combination of mechanical properties at room temperature. Further research on MAM for the production of critical parts made of Ti2AlNb-based alloys can be focused on a detailed study of the influence of post-processing and chemical composition on the formation of the structure and mechanical properties, including cyclic loading, fracture toughness, and creep resistance

Geodynamic Settings of Late Paleozoic–Early Mesozoic Granitoid Magmatism at the Arctic Continental Margins: Insights from New Geochronological and Geochemical Data from the Taimyr Peninsula

Despite significant progress in Arctic geological studies, a number of principal questions concerning the Paleozoic collisional events remain unanswered. Therefore, the Taimyr Peninsula, representing the only outcropped high Arctic region where magmatic complexes, formed by Hercynian collision between the Siberian Craton and the Kara Block, are well exposed, is crucially important. In this paper we report new geochemical and geochronological data for intrusions in the poorly studied northeastern part of the Taimyr Peninsula. The obtained results in combination with published data show that supra-subduction magmatism at the southern active margin of the Kara Block continued from ca. 345 to 285 Ma (Early Carboniferous to Early Permian), and was followed by a post-collisional magmatic pulse that affected the whole Taimyr across terrane boundaries at ca. 280 Ma in the Early Permian. After cessation of the post-collisional magmatism at ca. 265 Ma, the Taimyr experienced extension, and voluminous magmatic series associated with a Siberian mantle plume were formed between 251 and 228 Ma during the Triassic. The studied post-collisional and plume-related intrusions of the Northeastern Taimyr are generally classified as evolved high-K I-type granites with adakitic affinity. The latter is a regional feature because the majority of the analyzed plume-related granitoids are geochemically similar to high potassium continental adakites. It is suggested that the adakitic geochemical characteristics of the plume-related granitoids resulted from melting of hydrated mafic lower crustal protoliths and were controlled by the source lithology. Comparison of the new results with data available for adjacent areas allows for correlation of terranes on a regional scale and sheds light on the evolution of the Arctic continental margins in general. In the Early–Middle Paleozoic, the Kara Block was part of a continental terrane that formed at the northern edge of Baltica as a result of Neoproterozoic Timanian orogeny. In the Early Carboniferous, the southern margin of Kara turned into an active margin, while its inferred continuation in the eastern Uralian margin of Baltica remained a passive margin until the Early Permian. This discrepancy can be explained by dextral displacement of Kara relative to Baltica that took place in the Early Carboniferous and was later accommodated by the formation of the Taimyr collisional belt in the course of the Early Permian collision between Kara and Siberia. After collision, the Taimyr was incorporated into the northern Eurasian margin as an uplifted block that experienced surface erosion and supplied clastic material in surrounding basins