Papers by Keyword: Interlayer

Abstract: The contact between the original and the new concrete layer is important from the point of view of the load-bearing capacity of the composite cross-section. In practice, we encounter that when reinforcing a concrete element with a new layer of concrete, the element is considered as a single cross-section, so no slippage between the individual layers is assumed. This article deals with numerical modeling of two contact variants. The first alternative is modeling according to the im-plemented module which contains the 3D program ATENA Cervenka Consulting and the second is using an intermediate layer and subsequent comparison of modeling methods with a real experiment.

Abstract: The article is aimed at studying the distribution of deformation work in the layers of the explosion-welded composite Al-Cr-St3 with a diffusion barrier. It is established that the thickness of the chromium layer does not affect the value of the total deformation work. An increase in the thickness of the chromium interlayer leads to a decrease in the proportion of deformation work and strength.

Abstract: This paper introduces characteristics of common repairment method for oil and gas transmission pipeline, especially for steel reinforcement repair sleeve. In this research, an X80 pipe with interlayer defects repaired by steel reinforcement repair sleeve was studied. In order to investigate the repair effect of steel reinforcement repair sleeve for interlayer defects, a hydraulic blasting test and metallographic analysis for repaired pipeline were performed. The result shows that interlayer defect influences the pressure capacity of pipe to a certain degree, however, steel reinforcement repair sleeve could provide an acceptable strengthening to the repaired section.

Abstract: Metal matrix composites have attracted interest for use in several engineering applications and this study focuses on the fabrication titanium and interstitial free steel composite and its mechanical performance. Accumulative roll bonding (ARB) was employed as a severe plastic deformation method to fabricate the multi-layered composite up to three cycles where an aluminum alloy is utilized as an interlayer material. Improvement in hardness and strength levels was achieved with an increased number of ARB cycles. Although, the composite obtained after three cycles indicated a brittle behavior, a decent tensile response of around 650 MPa and 10% ductility was demonstrated after two ARB cycles.

Abstract: Herein, solid-state diffusion-coupled joints (DCJs) were prepared in vacuum between stainless steel (SS) and Ti6Al4V by means of a pure niobium (Nb) interlayer (~200-μm thickness) using uni-axial compressive pressure of 4 MPa at 875 °C for 15 to 120 min. Interfacial characterization revealed the existence of successive layer wise Fe–Nb-based intermetallics like FeNb+(Nb) and Fe₂Nb at Nb|SS interfaces of DCJs processed from 60 to 120 min, but the DCJs processed for shorter duration (from 15 to 30 min) do not reveal any intermetallics; however, the DCJs processed for 45 min revealed a single reaction layer of FeNb whereas that of Ti6Al4V|Nb interfaces revealed solid solution behaviour for all bonding time intervals. Required chemical analysis (in at. pct) of the reaction products was found out using spectroscope and X-ray diffractometer. Mechanical characterization (at 32 °C) of the DCJs was carried out with a microhardness tester and tensile testing facility. Ti6Al4V|Nb interface experienced a hardness of ~298 HV (for all bonding time), whereas Nb|SS interface experienced ~200 HV for 15 and 30 min and ~650 HV for 45 min and longer. DCJs treated for 60 min have better strength properties. Manifestation of reaction layers: FeNb, FeNb+(Nb), and Fe₂Nb have significant effect on the strength. From the interfacial microhardness, path and surface of fracture surfaces characterizations, it was revealed that failure of the DCJs was transmitted seemingly along Nb|SS interfaces. The analytical finding of intrinsic diffusivity of Ti atoms in Nb along Ti6Al4V|Nb interface is higher by one order of magnitude than the diffusivity results of Fe atoms in Nb along the Nb|SS interface. Experimental evidences show that the growth of the reaction products along Ti6Al4V|Nb interface (adj. R-Square=0.982) and Nb|SS interface (adj. R-Square=0.999) follows a parabolic law. Recently, researchers considered diffusion coupling as the key technology to fabricate Ti|Al|Al-C_f biomimetic structure, graphite|Nb|Cu for fusion reactor devices, Ni|Ni₃Al for MEMS applications, hybrid heat exchangers for nuclear applications, etc.

Abstract: The effect of Li and Sr impurities on the kinetics and structure formation of alloys in the Sn - Pb, In - Zn, Sn - Zn systems used in the soldering of instrument nodes in electronics has been investigated. The XPS method showed that under the given experimental conditions and the indicated concentrations of lithium impurities in lead and strontium in zinc, there are no prerequisites for the formation of chemical compounds, which is explained by an insignificant impurity content, although a significant amount of chemical compounds is formed according to state diagrams. It was also established that impurities affect the kinetics of phase growth in the junction zone.

Abstract: Mesoporous silica (MPS) coatings on β-tricalcium phosphate (β-TCP) granules and their protein adsorptive capabilities were studied. β-TCP granules containing 2 wt% of aluminum oxide and 6 wt% of silicon oxide were prepared using a pan-type granulator and heated at 1200 oC. MPS coatings on β-TCP granules was carried out by a dip-coating method, but the β-TCP granules were not covered by the MPS particles. A silica interlayer was formed on the β-TCP granules via magnetron sputtering prior to the coating of the MPS. The β-TCP granules coated with the silica interlayer were fully covered by the MPS particles. A silica interlayer may offer bonding between the β-TCP granules and MPS coating. The adsorption of protein on the MPS-coated β-TCP granules was evaluated by UV-VIS spectroscopy. The adsorption capacity of protein on the β-TCP granules was improved by the MPS coatings on the β-TCP granules, and that of the β-TCP granules coated with the silica interlayer showed a higher protein adsorption capacity.

Abstract: This paper reports comparative studies on effects of interlayer on mechanical properties of diamond-like carbon (DLC) coatings. Two interlayers, TiC/Ti and CrC/Cr, were deposited and studied. The DLC coatings were prepared by using an unbalanced magnetron sputtering system. The chemical composition, micro-structure, constituted phases, and fundamental mechanical and tribological properties were evaluated. The results showed that the two amorphous (a-) DLC coatings were obtained. The a-DLC coating with the TiC/Ti interlayer showed higher adhesion, hardness and wear resistance than the one with the CrC/Cr interlayer.

Abstract: In metallurgy and materials engineering, a number of phase transformation in solids like precipitation, oxidation, creep, annealing, homogenization, etc. are brought about by the process of diffusion. Many industrial manufacturing processes utilize solid-state diffusion principle, to name a few: 1. Rotating or sliding parts of steel have a hard outside case for wear resistance and a tough inner core for fracture resistance by gas carburizing procedure; 2. Integrated circuits were produced by diffusing impurity into silicon wafers; and 3. Joints between similar and dissimilar metals, alloys, and non-metals, were made using diffusion bonding (DB) technique. Day by day, the science of solid-state diffusion phenomenon is spreading inevitably into new areas of engineering and technology. Diffusion-Assisted-Joints (DAJs) meet the requirements for most critical structures in terms of strength, toughness, tightness, and resistance to heat and corrosion. DAJs can be made out of 730 pairs of dissimilar metals. Hence, DB is considered as an engineering marvel among all the physical welding metallurgists. Herein, experiments were performed to exactly map the quantum influence of the bonding temperature variation on the dissimilar joints of a popular light alloy, Ti-6Al-4V (TiA), and a heavily used heavy alloy, stainless steel (SS), using diffusion mechanism in high-vacuum environment. Cu foil (~200 μm) was used as an interlayer. Necessary characterization tools for metallurgical investigations were used to understand the extent of diffusion along the TiA/Cu and Cu/SS interfaces, room-temperature mechanical properties, fracture morphologies, and fracture path of the TiA/Cu/SS DAJs. This paper discussed rational reasons backing the results of the characterizations.

Abstract: Mesoporous silica (MPS) coatings on hydroxyapatite (HAp) granules and their protein adsorptive capabilities were studied. MPS particles were coated on HAp granules using a dip-coating method, but the HAp granules were not totally covered by the MPS particles. A silica interlayer was formed on the HAp granules via magnetron sputtering or the sol-gel method prior to the coating of the MPS. The HAp granules coated with the silica interlayer were fully covered by the MPS particles. An silica interlayer may offer bonding between the HAp granules and MPS coating. The adsorption of protein on the MPS-coated HAp granules was evaluated by UV-VIS spectroscopy. The adsorption capacity of protein on the HAp granules was improved by the MPS coatings on the HAp granules, and that of the HAp granules coated with the silica interlayer showed a higher protein adsorption capacity.